diff --git a/src/main/java/org/apache/commons/collections4/map/MultiValueMap.java b/src/main/java/org/apache/commons/collections4/map/MultiValueMap.java
index af73df4b12..796f1b39be 100644
--- a/src/main/java/org/apache/commons/collections4/map/MultiValueMap.java
+++ b/src/main/java/org/apache/commons/collections4/map/MultiValueMap.java
@@ -134,7 +134,7 @@ public static <K, V, C extends Collection<V>> MultiValueMap<K, V> multiValueMap(
      */
     @SuppressWarnings({ "unchecked", "rawtypes" })
     public MultiValueMap() {
-        this(new HashMap<K, V>(), new ReflectionFactory(ArrayList.class));
+        this(new HashMap<>(), new ReflectionFactory(ArrayList.class));
     }
 
     /**
diff --git a/src/main/java/org/apache/commons/collections4/multimap/ArrayListValuedHashMap.java b/src/main/java/org/apache/commons/collections4/multimap/ArrayListValuedHashMap.java
index bc6b2700ad..0cc6a3718e 100644
--- a/src/main/java/org/apache/commons/collections4/multimap/ArrayListValuedHashMap.java
+++ b/src/main/java/org/apache/commons/collections4/multimap/ArrayListValuedHashMap.java
@@ -89,7 +89,7 @@ public ArrayListValuedHashMap(final int initialListCapacity) {
      * @param initialListCapacity  the initial capacity used for value collections
      */
     public ArrayListValuedHashMap(final int initialMapCapacity, final int initialListCapacity) {
-        super(new HashMap<K, ArrayList<V>>(initialMapCapacity));
+        super(new HashMap<>(initialMapCapacity));
         this.initialListCapacity = initialListCapacity;
     }
 
@@ -135,7 +135,7 @@ private void writeObject(final ObjectOutputStream oos) throws IOException {
 
     private void readObject(final ObjectInputStream ois) throws IOException, ClassNotFoundException {
         ois.defaultReadObject();
-        setMap(new HashMap<K, ArrayList<V>>());
+        setMap(new HashMap<>());
         doReadObject(ois);
     }
 
diff --git a/src/main/java/org/apache/commons/collections4/multimap/HashSetValuedHashMap.java b/src/main/java/org/apache/commons/collections4/multimap/HashSetValuedHashMap.java
index f6b8c16894..993defe1fb 100644
--- a/src/main/java/org/apache/commons/collections4/multimap/HashSetValuedHashMap.java
+++ b/src/main/java/org/apache/commons/collections4/multimap/HashSetValuedHashMap.java
@@ -88,7 +88,7 @@ public HashSetValuedHashMap(final int initialSetCapacity) {
      * @param initialSetCapacity  the initial capacity used for value collections
      */
     public HashSetValuedHashMap(final int initialMapCapacity, final int initialSetCapacity) {
-        super(new HashMap<K, HashSet<V>>(initialMapCapacity));
+        super(new HashMap<>(initialMapCapacity));
         this.initialSetCapacity = initialSetCapacity;
     }
 
@@ -124,7 +124,7 @@ private void writeObject(final ObjectOutputStream oos) throws IOException {
 
     private void readObject(final ObjectInputStream ois) throws IOException, ClassNotFoundException {
         ois.defaultReadObject();
-        setMap(new HashMap<K, HashSet<V>>());
+        setMap(new HashMap<>());
         doReadObject(ois);
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/ClosureUtilsTest.java b/src/test/java/org/apache/commons/collections4/ClosureUtilsTest.java
index dd89d26d34..f34021c340 100644
--- a/src/test/java/org/apache/commons/collections4/ClosureUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/ClosureUtilsTest.java
@@ -262,7 +262,7 @@ public void testSwitchClosure() {
         assertEquals(1, c.count);
 
         assertEquals(NOPClosure.INSTANCE, ClosureUtils.<String>switchClosure(new Predicate[0], new Closure[0]));
-        assertEquals(NOPClosure.INSTANCE, ClosureUtils.<String>switchClosure(new HashMap<Predicate<String>, Closure<String>>()));
+        assertEquals(NOPClosure.INSTANCE, ClosureUtils.<String>switchClosure(new HashMap<>()));
         map.clear();
         map.put(null, null);
         assertEquals(NOPClosure.INSTANCE, ClosureUtils.switchClosure(map));
@@ -309,7 +309,7 @@ public void testSwitchMapClosure() {
         assertEquals(0, b.count);
         assertEquals(1, c.count);
 
-        assertEquals(NOPClosure.INSTANCE, ClosureUtils.switchMapClosure(new HashMap<String, Closure<String>>()));
+        assertEquals(NOPClosure.INSTANCE, ClosureUtils.switchMapClosure(new HashMap<>()));
 
         assertThrows(NullPointerException.class, () -> ClosureUtils.switchMapClosure(null));
     }
diff --git a/src/test/java/org/apache/commons/collections4/CollectionUtilsTest.java b/src/test/java/org/apache/commons/collections4/CollectionUtilsTest.java
index de4480ec40..03d4fbe9dd 100644
--- a/src/test/java/org/apache/commons/collections4/CollectionUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/CollectionUtilsTest.java
@@ -313,12 +313,12 @@ public void collect() {
         assertCollectResult(collection);
 
         ArrayList<Number> list;
-        list = CollectionUtils.collect(collectionA, transformer, new ArrayList<Number>());
+        list = CollectionUtils.collect(collectionA, transformer, new ArrayList<>());
         assertEquals(list.size(), collectionA.size());
         assertCollectResult(list);
 
         Iterator<Integer> iterator = null;
-        list = CollectionUtils.collect(iterator, transformer, new ArrayList<Number>());
+        list = CollectionUtils.collect(iterator, transformer, new ArrayList<>());
 
         iterator = iterableA.iterator();
         list = CollectionUtils.collect(iterator, transformer, list);
@@ -1023,7 +1023,7 @@ private <T> void next(final Iterator<T> iterator, final T t) {
     @Test
     public void predicatedCollection() {
         final Predicate<Object> predicate = PredicateUtils.instanceofPredicate(Integer.class);
-        final Collection<Number> collection = CollectionUtils.predicatedCollection(new ArrayList<Number>(), predicate);
+        final Collection<Number> collection = CollectionUtils.predicatedCollection(new ArrayList<>(), predicate);
         assertTrue(collection instanceof PredicatedCollection, "returned object should be a PredicatedCollection");
     }
 
@@ -1047,7 +1047,7 @@ public void select() {
         // Ensure that the collection is the input type or a super type
         final Collection<Integer> output1 = CollectionUtils.select(list, EQUALS_TWO);
         final Collection<Number> output2 = CollectionUtils.<Number>select(list, EQUALS_TWO);
-        final HashSet<Number> output3 = CollectionUtils.select(list, EQUALS_TWO, new HashSet<Number>());
+        final HashSet<Number> output3 = CollectionUtils.select(list, EQUALS_TWO, new HashSet<>());
         assertTrue(CollectionUtils.isEqualCollection(output1, output3));
         assertEquals(4, list.size());
         assertEquals(1, output1.size());
@@ -1063,7 +1063,7 @@ public void selectRejected() {
         list.add(4L);
         final Collection<Long> output1 = CollectionUtils.selectRejected(list, EQUALS_TWO);
         final Collection<? extends Number> output2 = CollectionUtils.selectRejected(list, EQUALS_TWO);
-        final HashSet<Number> output3 = CollectionUtils.selectRejected(list, EQUALS_TWO, new HashSet<Number>());
+        final HashSet<Number> output3 = CollectionUtils.selectRejected(list, EQUALS_TWO, new HashSet<>());
         assertTrue(CollectionUtils.isEqualCollection(output1, output2));
         assertTrue(CollectionUtils.isEqualCollection(output1, output3));
         assertEquals(4, list.size());
diff --git a/src/test/java/org/apache/commons/collections4/IterableUtilsTest.java b/src/test/java/org/apache/commons/collections4/IterableUtilsTest.java
index 657d0bf20f..4a844b36f1 100644
--- a/src/test/java/org/apache/commons/collections4/IterableUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/IterableUtilsTest.java
@@ -432,7 +432,7 @@ public void testToString() {
         String result = IterableUtils.toString(iterableA);
         assertEquals("[1, 2, 2, 3, 3, 3, 4, 4, 4, 4]", result);
 
-        result = IterableUtils.toString(new ArrayList<Integer>());
+        result = IterableUtils.toString(new ArrayList<>());
         assertEquals("[]", result);
 
         result = IterableUtils.toString(null);
@@ -441,7 +441,7 @@ public void testToString() {
         result = IterableUtils.toString(iterableA, input -> Integer.toString(input * 2));
         assertEquals("[2, 4, 4, 6, 6, 6, 8, 8, 8, 8]", result);
 
-        result = IterableUtils.toString(new ArrayList<Integer>(), input -> {
+        result = IterableUtils.toString(new ArrayList<>(), input -> {
             fail("not supposed to reach here");
             return "";
         });
@@ -480,10 +480,10 @@ public void testToStringDelimiter() {
         result = IterableUtils.toString(iterableA, transformer, ",,", "((", "))");
         assertEquals("((2,,4,,4,,6,,6,,6,,8,,8,,8,,8))", result);
 
-        result = IterableUtils.toString(new ArrayList<Integer>(), transformer, "", "(", ")");
+        result = IterableUtils.toString(new ArrayList<>(), transformer, "", "(", ")");
         assertEquals("()", result);
 
-        result = IterableUtils.toString(new ArrayList<Integer>(), transformer, "", "", "");
+        result = IterableUtils.toString(new ArrayList<>(), transformer, "", "", "");
         assertEquals("", result);
     }
 
@@ -495,20 +495,20 @@ public void testToStringWithNullArguments() {
         }, "", "(", ")");
         assertEquals("()", result);
         assertAll(
-                () -> assertThrows(NullPointerException.class, () -> IterableUtils.toString(new ArrayList<Integer>(), null, "", "(", ")"),
+                () -> assertThrows(NullPointerException.class, () -> IterableUtils.toString(new ArrayList<>(), null, "", "(", ")"),
                         "expecting NullPointerException"),
                 () -> assertThrows(NullPointerException.class, () ->
-                                IterableUtils.toString(new ArrayList<Integer>(), input -> {
+                                IterableUtils.toString(new ArrayList<>(), input -> {
                                     fail("not supposed to reach here");
                                     return "";
                                 }, null, "(", ")"),
                         "expecting NullPointerException"),
-                () -> assertThrows(NullPointerException.class, () -> IterableUtils.toString(new ArrayList<Integer>(), input -> {
+                () -> assertThrows(NullPointerException.class, () -> IterableUtils.toString(new ArrayList<>(), input -> {
                     fail("not supposed to reach here");
                     return "";
                 }, "", null, ")"),
                         "expecting NullPointerException"),
-                () -> assertThrows(NullPointerException.class, () -> IterableUtils.toString(new ArrayList<Integer>(), input -> {
+                () -> assertThrows(NullPointerException.class, () -> IterableUtils.toString(new ArrayList<>(), input -> {
                     fail("not supposed to reach here");
                     return "";
                 }, "", "(", null),
diff --git a/src/test/java/org/apache/commons/collections4/ListUtilsTest.java b/src/test/java/org/apache/commons/collections4/ListUtilsTest.java
index 9ddb18c06b..00d5f58219 100644
--- a/src/test/java/org/apache/commons/collections4/ListUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/ListUtilsTest.java
@@ -209,7 +209,7 @@ public void testIntersectNonEmptyWithEmptyList() {
 
     @Test
     public void testLazyFactoryList() {
-        final List<Integer> list = ListUtils.lazyList(new ArrayList<Integer>(), new Factory<Integer>() {
+        final List<Integer> list = ListUtils.lazyList(new ArrayList<>(), new Factory<Integer>() {
 
             private int index;
 
@@ -406,7 +406,7 @@ public void testSelect() {
         // Ensure that the collection is the input type or a super type
         final List<Integer> output1 = ListUtils.select(list, EQUALS_TWO);
         final List<Number> output2 = ListUtils.<Number>select(list, EQUALS_TWO);
-        final HashSet<Number> output3 = CollectionUtils.select(list, EQUALS_TWO, new HashSet<Number>());
+        final HashSet<Number> output3 = CollectionUtils.select(list, EQUALS_TWO, new HashSet<>());
         assertTrue(CollectionUtils.isEqualCollection(output1, output3));
         assertEquals(4, list.size());
         assertEquals(1, output1.size());
@@ -423,7 +423,7 @@ public void testSelectRejected() {
         list.add(4L);
         final List<Long> output1 = ListUtils.selectRejected(list, EQUALS_TWO);
         final List<? extends Number> output2 = ListUtils.selectRejected(list, EQUALS_TWO);
-        final HashSet<Number> output3 = CollectionUtils.selectRejected(list, EQUALS_TWO, new HashSet<Number>());
+        final HashSet<Number> output3 = CollectionUtils.selectRejected(list, EQUALS_TWO, new HashSet<>());
         assertTrue(CollectionUtils.isEqualCollection(output1, output2));
         assertTrue(CollectionUtils.isEqualCollection(output1, output3));
         assertEquals(4, list.size());
diff --git a/src/test/java/org/apache/commons/collections4/MapUtilsTest.java b/src/test/java/org/apache/commons/collections4/MapUtilsTest.java
index 66b61c71d7..b81539a38d 100644
--- a/src/test/java/org/apache/commons/collections4/MapUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/MapUtilsTest.java
@@ -32,7 +32,6 @@
 import java.text.NumberFormat;
 import java.util.AbstractMap;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -167,11 +166,11 @@ public void testPutAll_Map_array() {
                 () -> assertThrows(NullPointerException.class, () -> MapUtils.putAll(null, new Object[0]))
         );
 
-        Map<String, String> test = MapUtils.putAll(new HashMap<String, String>(), org.apache.commons.lang3.ArrayUtils.EMPTY_STRING_ARRAY);
+        Map<String, String> test = MapUtils.putAll(new HashMap<>(), org.apache.commons.lang3.ArrayUtils.EMPTY_STRING_ARRAY);
         assertEquals(0, test.size());
 
         // sub array
-        test = MapUtils.putAll(new HashMap<String, String>(), new String[][] {
+        test = MapUtils.putAll(new HashMap<>(), new String[][] {
                 {"RED", "#FF0000"},
                 {"GREEN", "#00FF00"},
                 {"BLUE", "#0000FF"}
@@ -184,17 +183,17 @@ public void testPutAll_Map_array() {
         assertEquals("#0000FF", test.get("BLUE"));
         assertEquals(3, test.size());
         assertAll(
-                () -> assertThrows(IllegalArgumentException.class, () -> MapUtils.putAll(new HashMap<String, String>(), new String[][]{
+                () -> assertThrows(IllegalArgumentException.class, () -> MapUtils.putAll(new HashMap<>(), new String[][]{
                         {"RED", "#FF0000"},
                     null,
                         {"BLUE", "#0000FF"}
                 })),
-                () -> assertThrows(IllegalArgumentException.class, () -> MapUtils.putAll(new HashMap<String, String>(), new String[][]{
+                () -> assertThrows(IllegalArgumentException.class, () -> MapUtils.putAll(new HashMap<>(), new String[][]{
                         {"RED", "#FF0000"},
                         {"GREEN"},
                         {"BLUE", "#0000FF"}
                 })),
-                () -> assertThrows(IllegalArgumentException.class, () -> MapUtils.putAll(new HashMap<String, String>(), new String[][]{
+                () -> assertThrows(IllegalArgumentException.class, () -> MapUtils.putAll(new HashMap<>(), new String[][]{
                         {"RED", "#FF0000"},
                         {},
                         {"BLUE", "#0000FF"}
@@ -202,7 +201,7 @@ public void testPutAll_Map_array() {
         );
 
         // flat array
-        test = MapUtils.putAll(new HashMap<String, String>(), new String[] {
+        test = MapUtils.putAll(new HashMap<>(), new String[] {
             "RED", "#FF0000",
             "GREEN", "#00FF00",
             "BLUE", "#0000FF"
@@ -215,7 +214,7 @@ public void testPutAll_Map_array() {
         assertEquals("#0000FF", test.get("BLUE"));
         assertEquals(3, test.size());
 
-        test = MapUtils.putAll(new HashMap<String, String>(), new String[] {
+        test = MapUtils.putAll(new HashMap<>(), new String[] {
             "RED", "#FF0000",
             "GREEN", "#00FF00",
             "BLUE", "#0000FF",
@@ -229,11 +228,11 @@ public void testPutAll_Map_array() {
         assertEquals("#0000FF", test.get("BLUE"));
         assertEquals(3, test.size());
 
-        test = MapUtils.putAll(new HashMap<String, String>(), null);
+        test = MapUtils.putAll(new HashMap<>(), null);
         assertEquals(0, test.size());
 
         // map entry
-        test = MapUtils.putAll(new HashMap<String, String>(), new Object[] {
+        test = MapUtils.putAll(new HashMap<>(), new Object[] {
             new DefaultMapEntry<>("RED", "#FF0000"),
             new DefaultMapEntry<>("GREEN", "#00FF00"),
             new DefaultMapEntry<>("BLUE", "#0000FF")
@@ -247,7 +246,7 @@ public void testPutAll_Map_array() {
         assertEquals(3, test.size());
 
         // key value
-        test = MapUtils.putAll(new HashMap<String, String>(), new Object[] {
+        test = MapUtils.putAll(new HashMap<>(), new Object[] {
             new DefaultKeyValue<>("RED", "#FF0000"),
             new DefaultKeyValue<>("GREEN", "#00FF00"),
             new DefaultKeyValue<>("BLUE", "#0000FF")
@@ -826,7 +825,7 @@ public void testPopulateMultiMap() {
         list.add(new X(5, "x5"));
 
         // Now test key transform population
-        final MultiValueMap<Integer, X> map = MultiValueMap.multiValueMap(new TreeMap<Integer, Collection<X>>());
+        final MultiValueMap<Integer, X> map = MultiValueMap.multiValueMap(new TreeMap<>());
         MapUtils.populateMap(map, list, (Transformer<X, Integer>) input -> input.key, TransformerUtils.<X>nopTransformer());
         assertEquals(list.size(), map.totalSize());
 
@@ -991,7 +990,7 @@ public void testFixedSizeMap() {
 
     @Test
     public void testFixedSizeSortedMap() {
-        final Exception exception = assertThrows(IllegalArgumentException.class, () -> MapUtils.fixedSizeSortedMap(new TreeMap<Long, Long>()).put(1L, 1L));
+        final Exception exception = assertThrows(IllegalArgumentException.class, () -> MapUtils.fixedSizeSortedMap(new TreeMap<>()).put(1L, 1L));
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java b/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
index c5a75c0bcf..7dfd82ed4e 100644
--- a/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
+++ b/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
@@ -233,7 +233,7 @@ public void testSwitchTransformer() {
         assertEquals("C", TransformerUtils.switchTransformer(map).transform("WELL"));
 
         assertEquals(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchTransformer(new Predicate[0], new Transformer[0]));
-        assertEquals(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchTransformer(new HashMap<Predicate<Object>, Transformer<Object, Object>>()));
+        assertEquals(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchTransformer(new HashMap<>()));
         map = new HashMap<>();
         map.put(null, null);
         assertEquals(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchTransformer(map));
@@ -263,7 +263,7 @@ public void testSwitchMapTransformer() {
         map.put(null, c);
         assertEquals("C", TransformerUtils.switchMapTransformer(map).transform("WELL"));
 
-        assertSame(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchMapTransformer(new HashMap<Object, Transformer<Object, Object>>()));
+        assertSame(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchMapTransformer(new HashMap<>()));
         map = new HashMap<>();
         map.put(null, null);
         assertSame(ConstantTransformer.NULL_INSTANCE, TransformerUtils.switchMapTransformer(map));
diff --git a/src/test/java/org/apache/commons/collections4/bag/CollectionBagTest.java b/src/test/java/org/apache/commons/collections4/bag/CollectionBagTest.java
index 2834422d9c..d88cb81264 100644
--- a/src/test/java/org/apache/commons/collections4/bag/CollectionBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/CollectionBagTest.java
@@ -49,7 +49,7 @@ public CollectionBagTest() {
 
     @Override
     public Bag<T> makeObject() {
-        return CollectionBag.collectionBag(new HashBag<T>());
+        return CollectionBag.collectionBag(new HashBag<>());
     }
 
     /**
diff --git a/src/test/java/org/apache/commons/collections4/bag/CollectionSortedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/CollectionSortedBagTest.java
index e3ee772e62..e65c2db8d5 100644
--- a/src/test/java/org/apache/commons/collections4/bag/CollectionSortedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/CollectionSortedBagTest.java
@@ -58,7 +58,7 @@ public boolean isNullSupported() {
 
     @Override
     public Bag<T> makeObject() {
-        return CollectionSortedBag.collectionSortedBag(new TreeBag<T>());
+        return CollectionSortedBag.collectionSortedBag(new TreeBag<>());
     }
 
     /**
diff --git a/src/test/java/org/apache/commons/collections4/bag/PredicatedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/PredicatedBagTest.java
index b37d0b8ed2..6379f464f2 100644
--- a/src/test/java/org/apache/commons/collections4/bag/PredicatedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/PredicatedBagTest.java
@@ -52,11 +52,11 @@ protected Bag<T> decorateBag(final HashBag<T> bag, final Predicate<T> predicate)
 
     @Override
     public Bag<T> makeObject() {
-        return decorateBag(new HashBag<T>(), truePredicate);
+        return decorateBag(new HashBag<>(), truePredicate);
     }
 
     protected Bag<T> makeTestBag() {
-        return decorateBag(new HashBag<T>(), stringPredicate());
+        return decorateBag(new HashBag<>(), stringPredicate());
     }
 
     @Override
@@ -104,7 +104,7 @@ public void testIllegalDecorate() {
 
         assertThrows(IllegalArgumentException.class, () -> decorateBag((HashBag<T>) elements, stringPredicate()));
 
-        assertThrows(NullPointerException.class, () -> decorateBag(new HashBag<T>(), null));
+        assertThrows(NullPointerException.class, () -> decorateBag(new HashBag<>(), null));
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/bag/PredicatedSortedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/PredicatedSortedBagTest.java
index 1362c85070..5d3b7cb566 100644
--- a/src/test/java/org/apache/commons/collections4/bag/PredicatedSortedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/PredicatedSortedBagTest.java
@@ -53,19 +53,19 @@ protected SortedBag<T> decorateBag(final SortedBag<T> bag, final Predicate<T> pr
 
     @Override
     public SortedBag<T> makeObject() {
-        return decorateBag(new TreeBag<T>(), truePredicate);
+        return decorateBag(new TreeBag<>(), truePredicate);
     }
 
     protected SortedBag<T> makeTestBag() {
-        return decorateBag(new TreeBag<T>(), stringPredicate());
+        return decorateBag(new TreeBag<>(), stringPredicate());
     }
 
     @Test
     public void testDecorate() {
-        final SortedBag<T> bag = decorateBag(new TreeBag<T>(), stringPredicate());
+        final SortedBag<T> bag = decorateBag(new TreeBag<>(), stringPredicate());
         ((PredicatedSortedBag<T>) bag).decorated();
 
-        assertThrows(NullPointerException.class, () -> decorateBag(new TreeBag<T>(), null));
+        assertThrows(NullPointerException.class, () -> decorateBag(new TreeBag<>(), null));
 
         assertThrows(NullPointerException.class, () -> decorateBag(nullBag, stringPredicate()));
     }
@@ -73,7 +73,7 @@ public void testDecorate() {
     @Test
     @SuppressWarnings("unchecked")
     public void testSortOrder() {
-        final SortedBag<T> bag = decorateBag(new TreeBag<T>(), stringPredicate());
+        final SortedBag<T> bag = decorateBag(new TreeBag<>(), stringPredicate());
         final String one = "one";
         final String two = "two";
         final String three = "three";
diff --git a/src/test/java/org/apache/commons/collections4/bag/SynchronizedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/SynchronizedBagTest.java
index 20a14a8753..5777ef2ea6 100644
--- a/src/test/java/org/apache/commons/collections4/bag/SynchronizedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/SynchronizedBagTest.java
@@ -33,7 +33,7 @@ public SynchronizedBagTest() {
 
     @Override
     public Bag<T> makeObject() {
-        return SynchronizedBag.synchronizedBag(new HashBag<T>());
+        return SynchronizedBag.synchronizedBag(new HashBag<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/bag/TransformedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/TransformedBagTest.java
index ea7fc8558d..08cf707f80 100644
--- a/src/test/java/org/apache/commons/collections4/bag/TransformedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/TransformedBagTest.java
@@ -40,7 +40,7 @@ public TransformedBagTest() {
     @Override
     @SuppressWarnings("unchecked")
     public Bag<T> makeObject() {
-        return TransformedBag.transformingBag(new HashBag<T>(),
+        return TransformedBag.transformingBag(new HashBag<>(),
                 (Transformer<T, T>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
@@ -53,7 +53,7 @@ protected int getIterationBehaviour() {
     @SuppressWarnings("unchecked")
     public void testTransformedBag() {
         //T had better be Object!
-        final Bag<T> bag = TransformedBag.transformingBag(new HashBag<T>(),
+        final Bag<T> bag = TransformedBag.transformingBag(new HashBag<>(),
                 (Transformer<T, T>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertTrue(bag.isEmpty());
         final Object[] els = {"1", "3", "5", "7", "2", "4", "6"};
diff --git a/src/test/java/org/apache/commons/collections4/bag/TransformedSortedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/TransformedSortedBagTest.java
index ebac0fedea..e6399488c1 100644
--- a/src/test/java/org/apache/commons/collections4/bag/TransformedSortedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/TransformedSortedBagTest.java
@@ -39,13 +39,13 @@ public TransformedSortedBagTest() {
     @Override
     @SuppressWarnings("unchecked")
     public SortedBag<T> makeObject() {
-        return TransformedSortedBag.transformingSortedBag(new TreeBag<T>(), (Transformer<T, T>) TransformedCollectionTest.NOOP_TRANSFORMER);
+        return TransformedSortedBag.transformingSortedBag(new TreeBag<>(), (Transformer<T, T>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
     @Test
     @SuppressWarnings("unchecked")
     public void testTransformedBag() {
-        final SortedBag<T> bag = TransformedSortedBag.transformingSortedBag(new TreeBag<T>(), (Transformer<T, T>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
+        final SortedBag<T> bag = TransformedSortedBag.transformingSortedBag(new TreeBag<>(), (Transformer<T, T>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, bag.size());
         final Object[] els = {"1", "3", "5", "7", "2", "4", "6"};
         for (int i = 0; i < els.length; i++) {
diff --git a/src/test/java/org/apache/commons/collections4/bag/UnmodifiableBagTest.java b/src/test/java/org/apache/commons/collections4/bag/UnmodifiableBagTest.java
index 24625c643f..73eb45edf9 100644
--- a/src/test/java/org/apache/commons/collections4/bag/UnmodifiableBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/UnmodifiableBagTest.java
@@ -41,7 +41,7 @@ public UnmodifiableBagTest() {
 
     @Override
     public Bag<E> makeObject() {
-        return UnmodifiableBag.unmodifiableBag(new HashBag<E>());
+        return UnmodifiableBag.unmodifiableBag(new HashBag<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/bag/UnmodifiableSortedBagTest.java b/src/test/java/org/apache/commons/collections4/bag/UnmodifiableSortedBagTest.java
index f5153dee57..6a7a8667c1 100644
--- a/src/test/java/org/apache/commons/collections4/bag/UnmodifiableSortedBagTest.java
+++ b/src/test/java/org/apache/commons/collections4/bag/UnmodifiableSortedBagTest.java
@@ -41,7 +41,7 @@ public UnmodifiableSortedBagTest() {
 
     @Override
     public SortedBag<E> makeObject() {
-        return UnmodifiableSortedBag.unmodifiableSortedBag(new TreeBag<E>());
+        return UnmodifiableSortedBag.unmodifiableSortedBag(new TreeBag<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/bidimap/AbstractOrderedBidiMapDecoratorTest.java b/src/test/java/org/apache/commons/collections4/bidimap/AbstractOrderedBidiMapDecoratorTest.java
index 99e5401f45..48048b1342 100644
--- a/src/test/java/org/apache/commons/collections4/bidimap/AbstractOrderedBidiMapDecoratorTest.java
+++ b/src/test/java/org/apache/commons/collections4/bidimap/AbstractOrderedBidiMapDecoratorTest.java
@@ -70,7 +70,7 @@ private static final class TestOrderedBidiMap<K, V> extends AbstractOrderedBidiM
         private TestOrderedBidiMap<V, K> inverse = null;
 
         TestOrderedBidiMap() {
-            super(new DualTreeBidiMap<K, V>());
+            super(new DualTreeBidiMap<>());
         }
 
         TestOrderedBidiMap(final OrderedBidiMap<K, V> map) {
diff --git a/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableBidiMapTest.java b/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableBidiMapTest.java
index 3fbac8976c..cdb3b8859b 100644
--- a/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableBidiMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableBidiMapTest.java
@@ -39,7 +39,7 @@ public UnmodifiableBidiMapTest() {
 
     @Override
     public BidiMap<K, V> makeObject() {
-        return UnmodifiableBidiMap.unmodifiableBidiMap(new DualHashBidiMap<K, V>());
+        return UnmodifiableBidiMap.unmodifiableBidiMap(new DualHashBidiMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableOrderedBidiMapTest.java b/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableOrderedBidiMapTest.java
index cd5782ddf2..9c78113139 100644
--- a/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableOrderedBidiMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableOrderedBidiMapTest.java
@@ -38,7 +38,7 @@ public UnmodifiableOrderedBidiMapTest() {
 
     @Override
     public OrderedBidiMap<K, V> makeObject() {
-        return UnmodifiableOrderedBidiMap.unmodifiableOrderedBidiMap(new TreeBidiMap<K, V>());
+        return UnmodifiableOrderedBidiMap.unmodifiableOrderedBidiMap(new TreeBidiMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableSortedBidiMapTest.java b/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableSortedBidiMapTest.java
index 2a27da1eae..eb209a0ce9 100644
--- a/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableSortedBidiMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/bidimap/UnmodifiableSortedBidiMapTest.java
@@ -38,7 +38,7 @@ public UnmodifiableSortedBidiMapTest() {
 
     @Override
     public SortedBidiMap<K, V> makeObject() {
-        return UnmodifiableSortedBidiMap.unmodifiableSortedBidiMap(new DualTreeBidiMap<K, V>());
+        return UnmodifiableSortedBidiMap.unmodifiableSortedBidiMap(new DualTreeBidiMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/collection/IndexedCollectionTest.java b/src/test/java/org/apache/commons/collections4/collection/IndexedCollectionTest.java
index be52285817..cf96770746 100644
--- a/src/test/java/org/apache/commons/collections4/collection/IndexedCollectionTest.java
+++ b/src/test/java/org/apache/commons/collections4/collection/IndexedCollectionTest.java
@@ -61,7 +61,7 @@ public Integer transform(final String input) {
 
     @Override
     public Collection<String> makeObject() {
-        return decorateCollection(new ArrayList<String>());
+        return decorateCollection(new ArrayList<>());
     }
 
     @Override
@@ -90,11 +90,11 @@ public Collection<String> makeConfirmedFullCollection() {
     }
 
     public Collection<String> makeTestCollection() {
-        return decorateCollection(new ArrayList<String>());
+        return decorateCollection(new ArrayList<>());
     }
 
     public Collection<String> makeUniqueTestCollection() {
-        return decorateUniqueCollection(new ArrayList<String>());
+        return decorateUniqueCollection(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/collection/PredicatedCollectionTest.java b/src/test/java/org/apache/commons/collections4/collection/PredicatedCollectionTest.java
index 296a30a723..b259237be5 100644
--- a/src/test/java/org/apache/commons/collections4/collection/PredicatedCollectionTest.java
+++ b/src/test/java/org/apache/commons/collections4/collection/PredicatedCollectionTest.java
@@ -49,7 +49,7 @@ protected Collection<E> decorateCollection(
 
     @Override
     public Collection<E> makeObject() {
-        return decorateCollection(new ArrayList<E>(), truePredicate);
+        return decorateCollection(new ArrayList<>(), truePredicate);
     }
 
     @Override
@@ -78,7 +78,7 @@ public Collection<E> makeConfirmedFullCollection() {
         o -> o instanceof String;
 
     public Collection<E> makeTestCollection() {
-        return decorateCollection(new ArrayList<E>(), testPredicate);
+        return decorateCollection(new ArrayList<>(), testPredicate);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/collection/SynchronizedCollectionTest.java b/src/test/java/org/apache/commons/collections4/collection/SynchronizedCollectionTest.java
index 75f46507db..b7a1846823 100644
--- a/src/test/java/org/apache/commons/collections4/collection/SynchronizedCollectionTest.java
+++ b/src/test/java/org/apache/commons/collections4/collection/SynchronizedCollectionTest.java
@@ -34,7 +34,7 @@ public SynchronizedCollectionTest() {
 
     @Override
     public Collection<E> makeObject() {
-        return SynchronizedCollection.synchronizedCollection(new ArrayList<E>());
+        return SynchronizedCollection.synchronizedCollection(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/collection/UnmodifiableBoundedCollectionTest.java b/src/test/java/org/apache/commons/collections4/collection/UnmodifiableBoundedCollectionTest.java
index 1a43fd155c..719ade667f 100644
--- a/src/test/java/org/apache/commons/collections4/collection/UnmodifiableBoundedCollectionTest.java
+++ b/src/test/java/org/apache/commons/collections4/collection/UnmodifiableBoundedCollectionTest.java
@@ -41,7 +41,7 @@ public UnmodifiableBoundedCollectionTest() {
 
     @Override
     public Collection<E> makeObject() {
-        final BoundedCollection<E> coll = FixedSizeList.<E>fixedSizeList(new ArrayList<E>());
+        final BoundedCollection<E> coll = FixedSizeList.<E>fixedSizeList(new ArrayList<>());
         return UnmodifiableBoundedCollection.unmodifiableBoundedCollection(coll);
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/collection/UnmodifiableCollectionTest.java b/src/test/java/org/apache/commons/collections4/collection/UnmodifiableCollectionTest.java
index df0ed77aea..57b1913ea0 100644
--- a/src/test/java/org/apache/commons/collections4/collection/UnmodifiableCollectionTest.java
+++ b/src/test/java/org/apache/commons/collections4/collection/UnmodifiableCollectionTest.java
@@ -42,7 +42,7 @@ public UnmodifiableCollectionTest() {
 
     @Override
     public Collection<E> makeObject() {
-        return UnmodifiableCollection.unmodifiableCollection(new ArrayList<E>());
+        return UnmodifiableCollection.unmodifiableCollection(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/comparators/ReverseComparatorTest.java b/src/test/java/org/apache/commons/collections4/comparators/ReverseComparatorTest.java
index e485a8d9be..11f9a6d89b 100644
--- a/src/test/java/org/apache/commons/collections4/comparators/ReverseComparatorTest.java
+++ b/src/test/java/org/apache/commons/collections4/comparators/ReverseComparatorTest.java
@@ -81,7 +81,7 @@ public List<Integer> getComparableObjectsOrdered() {
     @Test
     @Override
     public void testSerializeDeserializeThenCompare() throws Exception {
-        final Comparator<?> comp = new ReverseComparator<>(new ComparableComparator<String>());
+        final Comparator<?> comp = new ReverseComparator<>(new ComparableComparator<>());
 
         final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
         final ObjectOutputStream out = new ObjectOutputStream(buffer);
diff --git a/src/test/java/org/apache/commons/collections4/functors/ComparatorPredicateTest.java b/src/test/java/org/apache/commons/collections4/functors/ComparatorPredicateTest.java
index 90cc57c04a..49603dd478 100644
--- a/src/test/java/org/apache/commons/collections4/functors/ComparatorPredicateTest.java
+++ b/src/test/java/org/apache/commons/collections4/functors/ComparatorPredicateTest.java
@@ -36,7 +36,7 @@ public int compare(final T first, final T second) {
     @Test
     public void compareEquals() {
         final Integer value = Integer.valueOf(10);
-        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<Integer>());
+        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<>());
         assertPredicateFalse(p, Integer.valueOf(value.intValue() - 1));
         assertPredicateTrue(p, Integer.valueOf(value.intValue()));
         assertPredicateFalse(p, Integer.valueOf(value.intValue() + 1));
@@ -45,7 +45,7 @@ public void compareEquals() {
     @Test
     public void compareGreater() {
         final Integer value = Integer.valueOf(10);
-        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<Integer>(), Criterion.GREATER);
+        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<>(), Criterion.GREATER);
         assertPredicateTrue(p, Integer.valueOf(value.intValue() - 1));
         assertPredicateFalse(p, Integer.valueOf(value.intValue()));
         assertPredicateFalse(p, Integer.valueOf(value.intValue() + 1));
@@ -54,7 +54,7 @@ public void compareGreater() {
     @Test
     public void compareLess() {
         final Integer value = Integer.valueOf(10);
-        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<Integer>(), Criterion.LESS);
+        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<>(), Criterion.LESS);
         assertPredicateFalse(p, Integer.valueOf(value.intValue() - 1));
         assertPredicateFalse(p, Integer.valueOf(value.intValue()));
         assertPredicateTrue(p, Integer.valueOf(value.intValue() + 1));
@@ -63,7 +63,7 @@ public void compareLess() {
     @Test
     public void compareGreaterOrEqual() {
         final Integer value = Integer.valueOf(10);
-        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<Integer>(), Criterion.GREATER_OR_EQUAL);
+        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<>(), Criterion.GREATER_OR_EQUAL);
         assertPredicateTrue(p, Integer.valueOf(value.intValue() - 1));
         assertPredicateTrue(p, Integer.valueOf(value.intValue()));
         assertPredicateFalse(p, Integer.valueOf(value.intValue() + 1));
@@ -72,7 +72,7 @@ public void compareGreaterOrEqual() {
     @Test
     public void compareLessOrEqual() {
         final Integer value = Integer.valueOf(10);
-        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<Integer>(), Criterion.LESS_OR_EQUAL);
+        final Predicate<Integer> p = comparatorPredicate(value, new TestComparator<>(), Criterion.LESS_OR_EQUAL);
         assertPredicateFalse(p, Integer.valueOf(value.intValue() - 1));
         assertPredicateTrue(p, Integer.valueOf(value.intValue()));
         assertPredicateTrue(p, Integer.valueOf(value.intValue() + 1));
@@ -80,6 +80,6 @@ public void compareLessOrEqual() {
 
     @Override
     protected Predicate<?> generatePredicate() {
-        return comparatorPredicate(Integer.valueOf(10), new TestComparator<Integer>());
+        return comparatorPredicate(Integer.valueOf(10), new TestComparator<>());
     }
 }
diff --git a/src/test/java/org/apache/commons/collections4/iterators/CollatingIteratorTest.java b/src/test/java/org/apache/commons/collections4/iterators/CollatingIteratorTest.java
index a87147edc4..a1a112830a 100644
--- a/src/test/java/org/apache/commons/collections4/iterators/CollatingIteratorTest.java
+++ b/src/test/java/org/apache/commons/collections4/iterators/CollatingIteratorTest.java
@@ -265,7 +265,7 @@ public void testNullComparator() {
 
         int i = 0;
         final CollatingIterator<Integer> collatingIterator2 = new CollatingIterator<>(null, l1.iterator(), l2.iterator());
-        collatingIterator2.setComparator(new ComparableComparator<Integer>());
+        collatingIterator2.setComparator(new ComparableComparator<>());
         for ( ; collatingIterator2.hasNext(); i++ ) {
             final Integer n = collatingIterator2.next();
             assertEquals((int) n, i + 1, "wrong order");
diff --git a/src/test/java/org/apache/commons/collections4/iterators/FilterIteratorTest.java b/src/test/java/org/apache/commons/collections4/iterators/FilterIteratorTest.java
index c91c399eeb..4d81b6b8e6 100644
--- a/src/test/java/org/apache/commons/collections4/iterators/FilterIteratorTest.java
+++ b/src/test/java/org/apache/commons/collections4/iterators/FilterIteratorTest.java
@@ -75,7 +75,7 @@ public void tearDown() throws Exception {
      */
     @Override
     public FilterIterator<E> makeEmptyIterator() {
-        return makeBlockAllFilter(new ArrayIterator<E>(array));
+        return makeBlockAllFilter(new ArrayIterator<>(array));
     }
 
     /**
diff --git a/src/test/java/org/apache/commons/collections4/iterators/FilterListIteratorTest.java b/src/test/java/org/apache/commons/collections4/iterators/FilterListIteratorTest.java
index 1be2aecb71..9ac73be842 100644
--- a/src/test/java/org/apache/commons/collections4/iterators/FilterListIteratorTest.java
+++ b/src/test/java/org/apache/commons/collections4/iterators/FilterListIteratorTest.java
@@ -185,7 +185,7 @@ public void testTruePredicate() {
     @Test
     public void testFalsePredicate() {
         final FilterListIterator<Integer> filtered = new FilterListIterator<>(list.listIterator(), falsePred);
-        walkLists(new ArrayList<Integer>(), filtered);
+        walkLists(new ArrayList<>(), filtered);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/iterators/PermutationIteratorTest.java b/src/test/java/org/apache/commons/collections4/iterators/PermutationIteratorTest.java
index be9c55a7e6..ac65d2e510 100644
--- a/src/test/java/org/apache/commons/collections4/iterators/PermutationIteratorTest.java
+++ b/src/test/java/org/apache/commons/collections4/iterators/PermutationIteratorTest.java
@@ -66,7 +66,7 @@ public boolean supportsEmptyIterator() {
 
     @Override
     public PermutationIterator<Character> makeEmptyIterator() {
-        return new PermutationIterator<>(new ArrayList<Character>());
+        return new PermutationIterator<>(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/iterators/ReverseListIteratorTest.java b/src/test/java/org/apache/commons/collections4/iterators/ReverseListIteratorTest.java
index 1c51164fce..4973c803a4 100644
--- a/src/test/java/org/apache/commons/collections4/iterators/ReverseListIteratorTest.java
+++ b/src/test/java/org/apache/commons/collections4/iterators/ReverseListIteratorTest.java
@@ -44,7 +44,7 @@ public ReverseListIteratorTest() {
 
     @Override
     public ListIterator<E> makeEmptyIterator() {
-        return new ReverseListIterator<>(new ArrayList<E>());
+        return new ReverseListIterator<>(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/list/FixedSizeListTest.java b/src/test/java/org/apache/commons/collections4/list/FixedSizeListTest.java
index 857d9596b0..9ed6ab4c42 100644
--- a/src/test/java/org/apache/commons/collections4/list/FixedSizeListTest.java
+++ b/src/test/java/org/apache/commons/collections4/list/FixedSizeListTest.java
@@ -41,7 +41,7 @@ public FixedSizeListTest() {
 
     @Override
     public List<E> makeObject() {
-        return FixedSizeList.fixedSizeList(new ArrayList<E>());
+        return FixedSizeList.fixedSizeList(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/list/PredicatedListTest.java b/src/test/java/org/apache/commons/collections4/list/PredicatedListTest.java
index f206bd3152..cc80cd366b 100644
--- a/src/test/java/org/apache/commons/collections4/list/PredicatedListTest.java
+++ b/src/test/java/org/apache/commons/collections4/list/PredicatedListTest.java
@@ -49,7 +49,7 @@ protected List<E> decorateList(final List<E> list, final Predicate<E> predicate)
 
     @Override
     public List<E> makeObject() {
-        return decorateList(new ArrayList<E>(), truePredicate);
+        return decorateList(new ArrayList<>(), truePredicate);
     }
 
     @Override
@@ -62,7 +62,7 @@ public E[] getFullElements() {
         o -> o instanceof String;
 
     public List<E> makeTestList() {
-        return decorateList(new ArrayList<E>(), testPredicate);
+        return decorateList(new ArrayList<>(), testPredicate);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/list/SetUniqueListTest.java b/src/test/java/org/apache/commons/collections4/list/SetUniqueListTest.java
index b6327a7d08..3da6f6d720 100644
--- a/src/test/java/org/apache/commons/collections4/list/SetUniqueListTest.java
+++ b/src/test/java/org/apache/commons/collections4/list/SetUniqueListTest.java
@@ -91,13 +91,13 @@ public E[] getFullNonNullElements() {
 
     @Override
     public List<E> makeObject() {
-        return new SetUniqueList<>(new ArrayList<E>(), new HashSet<E>());
+        return new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
     }
 
     @Test
     @SuppressWarnings("unchecked")
     public void testAdd() {
-        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<E>(), new HashSet<E>());
+        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
 
         // Duplicate element
         final E obj = (E) Integer.valueOf(1);
@@ -113,7 +113,7 @@ public void testAdd() {
     @Test
     @SuppressWarnings("unchecked")
     public void testAddAll() {
-        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<E>(), new HashSet<E>());
+        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
 
         lset.addAll(
             Arrays.asList((E[]) new Integer[] { Integer.valueOf(1), Integer.valueOf(1)}));
@@ -210,7 +210,7 @@ public void testCollections307() {
         // repeat the test with a different class than HashSet;
         // which means subclassing SetUniqueList below
         list = new ArrayList<>();
-        uniqueList = new SetUniqueList307(list, new TreeSet<E>());
+        uniqueList = new SetUniqueList307(list, new TreeSet<>());
 
         uniqueList.add((E) hello);
         uniqueList.add((E) world);
@@ -269,7 +269,7 @@ public void testFactory() {
     @Test
     public void testIntCollectionAddAll() {
         // make a SetUniqueList with one element
-        final List<Integer> list = new SetUniqueList<>(new ArrayList<Integer>(), new HashSet<Integer>());
+        final List<Integer> list = new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
         final Integer existingElement = Integer.valueOf(1);
         list.add(existingElement);
 
@@ -295,7 +295,7 @@ public void testIntCollectionAddAll() {
     @Test
     @SuppressWarnings("unchecked")
     public void testListIterator() {
-        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<E>(), new HashSet<E>());
+        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
 
         final E obj1 = (E) Integer.valueOf(1);
         final E obj2 = (E) Integer.valueOf(2);
@@ -424,7 +424,7 @@ public void testRetainAllWithInitialList() {
     @Test
     @SuppressWarnings("unchecked")
     public void testSet() {
-        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<E>(), new HashSet<E>());
+        final SetUniqueList<E> lset = new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
 
         // Duplicate element
         final E obj1 = (E) Integer.valueOf(1);
@@ -463,7 +463,7 @@ public void testSet() {
 
     @Test
     public void testSetCollections444() {
-        final SetUniqueList<Integer> lset = new SetUniqueList<>(new ArrayList<Integer>(), new HashSet<Integer>());
+        final SetUniqueList<Integer> lset = new SetUniqueList<>(new ArrayList<>(), new HashSet<>());
 
         // Duplicate element
         final Integer obj1 = Integer.valueOf(1);
@@ -594,7 +594,7 @@ public void testSubListIsUnmodifiable() {
     @Test
     @SuppressWarnings("unchecked")
     public void testUniqueListDoubleInsert() {
-        final List<E> l = SetUniqueList.setUniqueList(new LinkedList<E>());
+        final List<E> l = SetUniqueList.setUniqueList(new LinkedList<>());
         l.add((E) new Object());
         l.add((E) new Object());
 
@@ -610,7 +610,7 @@ public void testUniqueListDoubleInsert() {
     @Test
     @SuppressWarnings("unchecked")
     public void testUniqueListReInsert() {
-        final List<E> l = SetUniqueList.setUniqueList(new LinkedList<E>());
+        final List<E> l = SetUniqueList.setUniqueList(new LinkedList<>());
         l.add((E) new Object());
         l.add((E) new Object());
 
diff --git a/src/test/java/org/apache/commons/collections4/list/TransformedListTest.java b/src/test/java/org/apache/commons/collections4/list/TransformedListTest.java
index a40ba1ab3b..f8791db714 100644
--- a/src/test/java/org/apache/commons/collections4/list/TransformedListTest.java
+++ b/src/test/java/org/apache/commons/collections4/list/TransformedListTest.java
@@ -56,7 +56,7 @@ public List<E> makeConfirmedFullCollection() {
     @Override
     @SuppressWarnings("unchecked")
     public List<E> makeObject() {
-        return TransformedList.transformingList(new ArrayList<E>(), (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
+        return TransformedList.transformingList(new ArrayList<>(), (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
     @Override
@@ -69,7 +69,7 @@ public List<E> makeFullCollection() {
     @Test
     @SuppressWarnings("unchecked")
     public void testTransformedList() {
-        final List<E> list = TransformedList.transformingList(new ArrayList<E>(), (Transformer<E, E>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
+        final List<E> list = TransformedList.transformingList(new ArrayList<>(), (Transformer<E, E>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, list.size());
         final E[] els = (E[]) new Object[] {"1", "3", "5", "7", "2", "4", "6"};
         for (int i = 0; i < els.length; i++) {
diff --git a/src/test/java/org/apache/commons/collections4/list/UnmodifiableListTest.java b/src/test/java/org/apache/commons/collections4/list/UnmodifiableListTest.java
index d1ea995528..7f8397d147 100644
--- a/src/test/java/org/apache/commons/collections4/list/UnmodifiableListTest.java
+++ b/src/test/java/org/apache/commons/collections4/list/UnmodifiableListTest.java
@@ -41,7 +41,7 @@ public UnmodifiableListTest() {
 
     @Override
     public UnmodifiableList<E> makeObject() {
-        return new UnmodifiableList<>(new ArrayList<E>());
+        return new UnmodifiableList<>(new ArrayList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/map/AbstractMapTest.java b/src/test/java/org/apache/commons/collections4/map/AbstractMapTest.java
index 01f2d5a94d..06866838c7 100644
--- a/src/test/java/org/apache/commons/collections4/map/AbstractMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/AbstractMapTest.java
@@ -949,13 +949,13 @@ public void testMapPutAll() {
         // check putAll OK adding empty map to empty map
         resetEmpty();
         assertEquals(0, getMap().size());
-        getMap().putAll(new HashMap<K, V>());
+        getMap().putAll(new HashMap<>());
         assertEquals(0, getMap().size());
 
         // check putAll OK adding empty map to non-empty map
         resetFull();
         final int size = getMap().size();
-        getMap().putAll(new HashMap<K, V>());
+        getMap().putAll(new HashMap<>());
         assertEquals(size, getMap().size());
 
         // check putAll OK adding non-empty map to empty map
diff --git a/src/test/java/org/apache/commons/collections4/map/AbstractOrderedMapTest.java b/src/test/java/org/apache/commons/collections4/map/AbstractOrderedMapTest.java
index a0f99c7615..67265a9a65 100644
--- a/src/test/java/org/apache/commons/collections4/map/AbstractOrderedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/AbstractOrderedMapTest.java
@@ -71,7 +71,7 @@ public OrderedMap<K, V> makeFullMap() {
      */
     @Override
     public Map<K, V> makeConfirmedMap() {
-        return new TreeMap<>(new NullComparator<K>());
+        return new TreeMap<>(new NullComparator<>());
     }
 
     /**
@@ -82,7 +82,7 @@ public Map<K, V> makeConfirmedMap() {
     @SuppressWarnings("unchecked")
     public K[] getSampleKeys() {
         final List<K> list = new ArrayList<>(Arrays.asList(super.getSampleKeys()));
-        list.sort(new NullComparator<K>());
+        list.sort(new NullComparator<>());
         return (K[]) list.toArray();
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/map/CompositeMapTest.java b/src/test/java/org/apache/commons/collections4/map/CompositeMapTest.java
index ca6f5cb1bc..bbd56e9983 100644
--- a/src/test/java/org/apache/commons/collections4/map/CompositeMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/CompositeMapTest.java
@@ -51,8 +51,8 @@ public void setUp() throws Exception {
     @Override
     public CompositeMap<K, V> makeObject() {
         final CompositeMap<K, V> map = new CompositeMap<>();
-        map.addComposited(new HashMap<K, V>());
-        map.setMutator( new EmptyMapMutator<K, V>() );
+        map.addComposited(new HashMap<>());
+        map.setMutator( new EmptyMapMutator<>() );
         return map;
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/map/FixedSizeMapTest.java b/src/test/java/org/apache/commons/collections4/map/FixedSizeMapTest.java
index 5df607e019..589559c519 100644
--- a/src/test/java/org/apache/commons/collections4/map/FixedSizeMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/FixedSizeMapTest.java
@@ -35,7 +35,7 @@ public FixedSizeMapTest() {
 
     @Override
     public IterableMap<K, V> makeObject() {
-        return FixedSizeMap.fixedSizeMap(new HashMap<K, V>());
+        return FixedSizeMap.fixedSizeMap(new HashMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/map/FixedSizeSortedMapTest.java b/src/test/java/org/apache/commons/collections4/map/FixedSizeSortedMapTest.java
index 9597a107e2..7311977228 100644
--- a/src/test/java/org/apache/commons/collections4/map/FixedSizeSortedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/FixedSizeSortedMapTest.java
@@ -33,7 +33,7 @@ public FixedSizeSortedMapTest() {
 
     @Override
     public SortedMap<K, V> makeObject() {
-        return FixedSizeSortedMap.fixedSizeSortedMap(new TreeMap<K, V>());
+        return FixedSizeSortedMap.fixedSizeSortedMap(new TreeMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java b/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java
index e9798a2061..13311090db 100644
--- a/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/LazyMapTest.java
@@ -46,7 +46,7 @@ public LazyMapTest() {
 
     @Override
     public LazyMap<K, V> makeObject() {
-        return lazyMap(new HashMap<K, V>(), FactoryUtils.<V>nullFactory());
+        return lazyMap(new HashMap<>(), FactoryUtils.<V>nullFactory());
     }
 
     @Test
@@ -57,7 +57,7 @@ public void testMapGet() {
 
     @Test
     public void mapGetWithFactory() {
-        Map<Integer, Number> map = lazyMap(new HashMap<Integer, Number>(), oneFactory);
+        Map<Integer, Number> map = lazyMap(new HashMap<>(), oneFactory);
         assertEquals(0, map.size());
         final Number i1 = map.get("Five");
         assertEquals(1, i1);
@@ -67,7 +67,7 @@ public void mapGetWithFactory() {
         assertEquals(1, map.size());
         assertSame(i1, i2);
 
-        map = lazyMap(new HashMap<Integer, Number>(), FactoryUtils.<Long>nullFactory());
+        map = lazyMap(new HashMap<>(), FactoryUtils.<Long>nullFactory());
         final Object o = map.get("Five");
         assertNull(o);
         assertEquals(1, map.size());
@@ -76,7 +76,7 @@ public void mapGetWithFactory() {
     @Test
     public void mapGetWithTransformer() {
         final Transformer<Number, Integer> intConverter = Number::intValue;
-        final Map<Long, Number> map = lazyMap(new HashMap<Long, Number>(), intConverter);
+        final Map<Long, Number> map = lazyMap(new HashMap<>(), intConverter);
         assertEquals(0, map.size());
         final Number i1 = map.get(123L);
         assertEquals(123, i1);
diff --git a/src/test/java/org/apache/commons/collections4/map/LazySortedMapTest.java b/src/test/java/org/apache/commons/collections4/map/LazySortedMapTest.java
index 3de7c0df7e..bc21d916a2 100644
--- a/src/test/java/org/apache/commons/collections4/map/LazySortedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/LazySortedMapTest.java
@@ -64,7 +64,7 @@ public LazySortedMapTest() {
 
     @Override
     public SortedMap<K, V> makeObject() {
-        return lazySortedMap(new TreeMap<K, V>(), FactoryUtils.<V>nullFactory());
+        return lazySortedMap(new TreeMap<>(), FactoryUtils.<V>nullFactory());
     }
 
     @Override
@@ -81,13 +81,13 @@ public void testMapGet() {
 
     @Test
     public void mapGet() {
-        Map<Integer, Number> map = lazySortedMap(new TreeMap<Integer, Number>(), oneFactory);
+        Map<Integer, Number> map = lazySortedMap(new TreeMap<>(), oneFactory);
         assertEquals(0, map.size());
         final Number i1 = map.get(5);
         assertEquals(1, i1);
         assertEquals(1, map.size());
 
-        map = lazySortedMap(new TreeMap<Integer, Number>(), FactoryUtils.<Number>nullFactory());
+        map = lazySortedMap(new TreeMap<>(), FactoryUtils.<Number>nullFactory());
         final Number o = map.get(5);
         assertNull(o);
         assertEquals(1, map.size());
@@ -96,7 +96,7 @@ public void mapGet() {
 
     @Test
     public void testSortOrder() {
-        final SortedMap<String, Number> map = lazySortedMap(new TreeMap<String, Number>(), oneFactory);
+        final SortedMap<String, Number> map = lazySortedMap(new TreeMap<>(), oneFactory);
         map.put("A",  5);
         map.get("B"); // Entry with value "One" created
         map.put("C", 8);
@@ -115,7 +115,7 @@ public void testSortOrder() {
 
     @Test
     public void testReverseSortOrder() {
-        final SortedMap<String, Number> map = lazySortedMap(new ConcurrentSkipListMap<String, Number>(reverseStringComparator), oneFactory);
+        final SortedMap<String, Number> map = lazySortedMap(new ConcurrentSkipListMap<>(reverseStringComparator), oneFactory);
         map.put("A", 5);
         map.get("B"); // Entry with value "One" created
         map.put("C", 8);
@@ -135,10 +135,10 @@ public void testReverseSortOrder() {
     @Test
     public void testTransformerDecorate() {
         final Transformer<Object, Integer> transformer = TransformerUtils.asTransformer(oneFactory);
-        final SortedMap<Integer, Number> map = lazySortedMap(new TreeMap<Integer, Number>(), transformer);
+        final SortedMap<Integer, Number> map = lazySortedMap(new TreeMap<>(), transformer);
         assertTrue(map instanceof LazySortedMap);
         assertAll(
-                () -> assertThrows(NullPointerException.class, () -> lazySortedMap(new TreeMap<Integer, Number>(), (Transformer<Integer, Number>) null),
+                () -> assertThrows(NullPointerException.class, () -> lazySortedMap(new TreeMap<>(), (Transformer<Integer, Number>) null),
                         "Expecting NullPointerException for null transformer"),
                 () -> assertThrows(NullPointerException.class, () -> lazySortedMap((SortedMap<Integer, Number>) null, transformer),
                         "Expecting NullPointerException for null map")
diff --git a/src/test/java/org/apache/commons/collections4/map/ListOrderedMapTest.java b/src/test/java/org/apache/commons/collections4/map/ListOrderedMapTest.java
index 75e68733f3..8699c8f78c 100644
--- a/src/test/java/org/apache/commons/collections4/map/ListOrderedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/ListOrderedMapTest.java
@@ -47,7 +47,7 @@ public ListOrderedMapTest() {
 
     @Override
     public ListOrderedMap<K, V> makeObject() {
-        return ListOrderedMap.listOrderedMap(new HashMap<K, V>());
+        return ListOrderedMap.listOrderedMap(new HashMap<>());
     }
 
     /**
diff --git a/src/test/java/org/apache/commons/collections4/map/MultiKeyMapTest.java b/src/test/java/org/apache/commons/collections4/map/MultiKeyMapTest.java
index 68014853d6..5dff8ff4dc 100644
--- a/src/test/java/org/apache/commons/collections4/map/MultiKeyMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/MultiKeyMapTest.java
@@ -128,7 +128,7 @@ public void testNullHandling() {
 
         assertThrows(NullPointerException.class, () -> map.put(null, null));
 
-        assertNull(map.put(new MultiKey<K>(null, null), null));
+        assertNull(map.put(new MultiKey<>(null, null), null));
 
         assertThrows(NullPointerException.class, () -> map.put(null, (V) new Object()));
     }
@@ -437,7 +437,7 @@ public void testClone() {
     @Test
     @SuppressWarnings("unchecked")
     public void testLRUMultiKeyMap() {
-        final MultiKeyMap<K, V> map = MultiKeyMap.multiKeyMap(new LRUMap<MultiKey<? extends K>, V>(2));
+        final MultiKeyMap<K, V> map = MultiKeyMap.multiKeyMap(new LRUMap<>(2));
         map.put((K) I1, (K) I2, (V) "1-2");
         map.put((K) I1, (K) I3, (V) "1-1");
         assertEquals(2, map.size());
diff --git a/src/test/java/org/apache/commons/collections4/map/MultiValueMapTest.java b/src/test/java/org/apache/commons/collections4/map/MultiValueMapTest.java
index 262e40dde7..3283299bc8 100644
--- a/src/test/java/org/apache/commons/collections4/map/MultiValueMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/MultiValueMapTest.java
@@ -126,7 +126,7 @@ private MultiValueMap<K, V> createTestMap() {
 
     @SuppressWarnings("unchecked")
     private <C extends Collection<V>> MultiValueMap<K, V> createTestMap(final Class<C> collectionClass) {
-        final MultiValueMap<K, V> map = MultiValueMap.multiValueMap(new HashMap<K, C>(), collectionClass);
+        final MultiValueMap<K, V> map = MultiValueMap.multiValueMap(new HashMap<>(), collectionClass);
         map.put((K) "one", (V) "uno");
         map.put((K) "one", (V) "un");
         map.put((K) "two", (V) "dos");
@@ -308,7 +308,7 @@ public void testContainsValue_Key() {
     @SuppressWarnings("unchecked")
     public void testPutWithList() {
         @SuppressWarnings("rawtypes")
-        final MultiValueMap<K, V> test = MultiValueMap.multiValueMap(new HashMap<K, Collection>(), ArrayList.class);
+        final MultiValueMap<K, V> test = MultiValueMap.multiValueMap(new HashMap<>(), ArrayList.class);
         assertEquals("a", test.put((K) "A", "a"));
         assertEquals("b", test.put((K) "A", "b"));
         assertEquals(1, test.size());
@@ -320,7 +320,7 @@ public void testPutWithList() {
     @SuppressWarnings("unchecked")
     public void testPutWithSet() {
         @SuppressWarnings("rawtypes")
-        final MultiValueMap<K, V> test = MultiValueMap.multiValueMap(new HashMap<K, HashSet>(), HashSet.class);
+        final MultiValueMap<K, V> test = MultiValueMap.multiValueMap(new HashMap<>(), HashSet.class);
         assertEquals("a", test.put((K) "A", "a"));
         assertEquals("b", test.put((K) "A", "b"));
         assertNull(test.put((K) "A", "a"));
@@ -392,7 +392,7 @@ public void testPutAll_KeyCollection() {
         assertTrue(map.containsValue("A", "Y"));
         assertTrue(map.containsValue("A", "Z"));
 
-        assertFalse(map.putAll((K) "A", new ArrayList<V>()));
+        assertFalse(map.putAll((K) "A", new ArrayList<>()));
         assertEquals(3, map.size("A"));
         assertTrue(map.containsValue("A", "X"));
         assertTrue(map.containsValue("A", "Y"));
@@ -419,7 +419,7 @@ public void testRemove_KeyItem() {
         assertTrue(map.removeMapping("A", "AC"));
         assertTrue(map.removeMapping("A", "AB"));
         assertTrue(map.removeMapping("A", "AA"));
-        assertEquals(new MultiValueMap<K, V>(), map);
+        assertEquals(new MultiValueMap<>(), map);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/map/PassiveExpiringMapTest.java b/src/test/java/org/apache/commons/collections4/map/PassiveExpiringMapTest.java
index c92f1286ae..3447e40d72 100644
--- a/src/test/java/org/apache/commons/collections4/map/PassiveExpiringMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/PassiveExpiringMapTest.java
@@ -191,12 +191,12 @@ public void testEntrySet() {
 
     @Test
     public void testExpiration() {
-        validateExpiration(new PassiveExpiringMap<String, String>(500), 500);
-        validateExpiration(new PassiveExpiringMap<String, String>(1000), 1000);
+        validateExpiration(new PassiveExpiringMap<>(500), 500);
+        validateExpiration(new PassiveExpiringMap<>(1000), 1000);
         validateExpiration(new PassiveExpiringMap<>(
-                new PassiveExpiringMap.ConstantTimeToLiveExpirationPolicy<String, String>(500)), 500);
+                new PassiveExpiringMap.ConstantTimeToLiveExpirationPolicy<>(500)), 500);
         validateExpiration(new PassiveExpiringMap<>(
-                new PassiveExpiringMap.ConstantTimeToLiveExpirationPolicy<String, String>(1, TimeUnit.SECONDS)), 1000);
+                new PassiveExpiringMap.ConstantTimeToLiveExpirationPolicy<>(1, TimeUnit.SECONDS)), 1000);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/map/PredicatedMapTest.java b/src/test/java/org/apache/commons/collections4/map/PredicatedMapTest.java
index 65581fdc51..1b9968b859 100644
--- a/src/test/java/org/apache/commons/collections4/map/PredicatedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/PredicatedMapTest.java
@@ -53,11 +53,11 @@ protected IterableMap<K, V> decorateMap(final Map<K, V> map, final Predicate<? s
 
     @Override
     public IterableMap<K, V> makeObject() {
-        return decorateMap(new HashMap<K, V>(), truePredicate, truePredicate);
+        return decorateMap(new HashMap<>(), truePredicate, truePredicate);
     }
 
     public IterableMap<K, V> makeTestMap() {
-        return decorateMap(new HashMap<K, V>(), testPredicate, testPredicate);
+        return decorateMap(new HashMap<>(), testPredicate, testPredicate);
     }
 
     @Test
@@ -65,7 +65,7 @@ public IterableMap<K, V> makeTestMap() {
     public void testEntrySet() {
         Map<K, V> map = makeTestMap();
         assertNotNull(map.entrySet(), "returned entryset should not be null");
-        map = decorateMap(new HashMap<K, V>(), null, null);
+        map = decorateMap(new HashMap<>(), null, null);
         map.put((K) "oneKey", (V) "oneValue");
         assertEquals(1, map.entrySet().size(), "returned entryset should contain one entry");
         map = decorateMap(map, null, null);
diff --git a/src/test/java/org/apache/commons/collections4/map/PredicatedSortedMapTest.java b/src/test/java/org/apache/commons/collections4/map/PredicatedSortedMapTest.java
index 887ca820b2..51e7d50c1a 100644
--- a/src/test/java/org/apache/commons/collections4/map/PredicatedSortedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/PredicatedSortedMapTest.java
@@ -67,15 +67,15 @@ protected SortedMap<K, V> decorateMap(final SortedMap<K, V> map, final Predicate
 
     @Override
     public SortedMap<K, V> makeObject() {
-        return decorateMap(new TreeMap<K, V>(), truePredicate, truePredicate);
+        return decorateMap(new TreeMap<>(), truePredicate, truePredicate);
     }
 
     public SortedMap<K, V> makeTestMap() {
-        return decorateMap(new TreeMap<K, V>(), testPredicate, testPredicate);
+        return decorateMap(new TreeMap<>(), testPredicate, testPredicate);
     }
 
     public SortedMap<K, V> makeTestMapWithComparator() {
-        return decorateMap(new ConcurrentSkipListMap<K, V>(reverseStringComparator), testPredicate, testPredicate);
+        return decorateMap(new ConcurrentSkipListMap<>(reverseStringComparator), testPredicate, testPredicate);
     }
 
     @Override
@@ -95,7 +95,7 @@ public boolean isAllowNullKey() {
     public void testEntrySet() {
         SortedMap<K, V> map = makeTestMap();
         assertNotNull(map.entrySet(), "returned entryset should not be null");
-        map = decorateMap(new TreeMap<K, V>(), null, null);
+        map = decorateMap(new TreeMap<>(), null, null);
         map.put((K) "oneKey", (V) "oneValue");
         assertEquals(1, map.entrySet().size(), "returned entryset should contain one entry");
         map = decorateMap(map, null, null);
diff --git a/src/test/java/org/apache/commons/collections4/map/SingletonMapTest.java b/src/test/java/org/apache/commons/collections4/map/SingletonMapTest.java
index 76c63062b9..44ebbaa7c6 100644
--- a/src/test/java/org/apache/commons/collections4/map/SingletonMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/SingletonMapTest.java
@@ -43,7 +43,7 @@ public SingletonMapTest() {
     public OrderedMap<K, V> makeObject() {
         // need an empty singleton map, but that's not possible
         // use a ridiculous fake instead to make the tests pass
-        return UnmodifiableOrderedMap.unmodifiableOrderedMap(ListOrderedMap.listOrderedMap(new HashMap<K, V>()));
+        return UnmodifiableOrderedMap.unmodifiableOrderedMap(ListOrderedMap.listOrderedMap(new HashMap<>()));
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/map/TransformedMapTest.java b/src/test/java/org/apache/commons/collections4/map/TransformedMapTest.java
index 61d07121b2..697de04567 100644
--- a/src/test/java/org/apache/commons/collections4/map/TransformedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/TransformedMapTest.java
@@ -45,7 +45,7 @@ public TransformedMapTest() {
 
     @Override
     public IterableMap<K, V> makeObject() {
-        return TransformedMap.transformingMap(new HashMap<K, V>(), TransformerUtils.<K>nopTransformer(),
+        return TransformedMap.transformingMap(new HashMap<>(), TransformerUtils.<K>nopTransformer(),
                 TransformerUtils.<V>nopTransformer());
     }
 
@@ -56,7 +56,7 @@ public void testTransformedMap() {
 
         Map<K, V> map = TransformedMap
                 .transformingMap(
-                        new HashMap<K, V>(),
+                        new HashMap<>(),
                         (Transformer<? super K, ? extends K>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER,
                         null);
         assertEquals(0, map.size());
diff --git a/src/test/java/org/apache/commons/collections4/map/TransformedSortedMapTest.java b/src/test/java/org/apache/commons/collections4/map/TransformedSortedMapTest.java
index 59a23022fc..5a53e68314 100644
--- a/src/test/java/org/apache/commons/collections4/map/TransformedSortedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/TransformedSortedMapTest.java
@@ -51,7 +51,7 @@ public String[] ignoredTests() {
     @Override
     @SuppressWarnings("unchecked")
     public SortedMap<K, V> makeObject() {
-        return TransformedSortedMap.transformingSortedMap(new TreeMap<K, V>(),
+        return TransformedSortedMap.transformingSortedMap(new TreeMap<>(),
                 (Transformer<? super K, ? extends K>) TransformerUtils.nopTransformer(),
                 (Transformer<? super V, ? extends V>) TransformerUtils.nopTransformer());
     }
@@ -69,7 +69,7 @@ public void testTransformedMap() {
 
         SortedMap<K, V> map = TransformedSortedMap
                 .transformingSortedMap(
-                        new TreeMap<K, V>(),
+                        new TreeMap<>(),
                         (Transformer<? super K, ? extends K>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER,
                         null);
         assertEquals(0, map.size());
@@ -90,7 +90,7 @@ public void testTransformedMap() {
 
         map = TransformedSortedMap
                 .transformingSortedMap(
-                        new TreeMap<K, V>(),
+                        new TreeMap<>(),
                         null,
                         (Transformer<? super V, ? extends V>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, map.size());
diff --git a/src/test/java/org/apache/commons/collections4/map/UnmodifiableMapTest.java b/src/test/java/org/apache/commons/collections4/map/UnmodifiableMapTest.java
index 74dc169382..fee8298076 100644
--- a/src/test/java/org/apache/commons/collections4/map/UnmodifiableMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/UnmodifiableMapTest.java
@@ -41,7 +41,7 @@ public UnmodifiableMapTest() {
 
     @Override
     public IterableMap<K, V> makeObject() {
-        return (IterableMap<K, V>) UnmodifiableMap.unmodifiableMap(new HashMap<K, V>());
+        return (IterableMap<K, V>) UnmodifiableMap.unmodifiableMap(new HashMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/map/UnmodifiableOrderedMapTest.java b/src/test/java/org/apache/commons/collections4/map/UnmodifiableOrderedMapTest.java
index 3ba205f445..cfe4c393a8 100644
--- a/src/test/java/org/apache/commons/collections4/map/UnmodifiableOrderedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/UnmodifiableOrderedMapTest.java
@@ -40,7 +40,7 @@ public UnmodifiableOrderedMapTest() {
 
     @Override
     public OrderedMap<K, V> makeObject() {
-        return UnmodifiableOrderedMap.unmodifiableOrderedMap(ListOrderedMap.listOrderedMap(new HashMap<K, V>()));
+        return UnmodifiableOrderedMap.unmodifiableOrderedMap(ListOrderedMap.listOrderedMap(new HashMap<>()));
     }
 
     @Override
@@ -60,7 +60,7 @@ public boolean isRemoveSupported() {
 
     @Override
     public OrderedMap<K, V> makeFullMap() {
-        final OrderedMap<K, V> m = ListOrderedMap.listOrderedMap(new HashMap<K, V>());
+        final OrderedMap<K, V> m = ListOrderedMap.listOrderedMap(new HashMap<>());
         addSampleMappings(m);
         return UnmodifiableOrderedMap.unmodifiableOrderedMap(m);
     }
diff --git a/src/test/java/org/apache/commons/collections4/map/UnmodifiableSortedMapTest.java b/src/test/java/org/apache/commons/collections4/map/UnmodifiableSortedMapTest.java
index f485d814eb..df1a86ec5d 100644
--- a/src/test/java/org/apache/commons/collections4/map/UnmodifiableSortedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/map/UnmodifiableSortedMapTest.java
@@ -40,7 +40,7 @@ public UnmodifiableSortedMapTest() {
 
     @Override
     public SortedMap<K, V> makeObject() {
-        return UnmodifiableSortedMap.unmodifiableSortedMap(new TreeMap<K, V>());
+        return UnmodifiableSortedMap.unmodifiableSortedMap(new TreeMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/multimap/AbstractMultiValuedMapTest.java b/src/test/java/org/apache/commons/collections4/multimap/AbstractMultiValuedMapTest.java
index e057cf8c6e..02f8ecd49f 100644
--- a/src/test/java/org/apache/commons/collections4/multimap/AbstractMultiValuedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/multimap/AbstractMultiValuedMapTest.java
@@ -660,7 +660,7 @@ public void testPutAll_KeyIterable() {
         assertTrue(map.containsMapping("A", "Y"));
         assertTrue(map.containsMapping("A", "Z"));
 
-        assertFalse(map.putAll((K) "A", new ArrayList<V>()));
+        assertFalse(map.putAll((K) "A", new ArrayList<>()));
         assertEquals(3, map.get((K) "A").size());
         assertTrue(map.containsMapping("A", "X"));
         assertTrue(map.containsMapping("A", "Y"));
diff --git a/src/test/java/org/apache/commons/collections4/multimap/TransformedMultiValuedMapTest.java b/src/test/java/org/apache/commons/collections4/multimap/TransformedMultiValuedMapTest.java
index 9a1acdf6c7..57f216b4fb 100644
--- a/src/test/java/org/apache/commons/collections4/multimap/TransformedMultiValuedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/multimap/TransformedMultiValuedMapTest.java
@@ -43,7 +43,7 @@ public TransformedMultiValuedMapTest() {
 
     @Override
     public MultiValuedMap<K, V> makeObject() {
-        return TransformedMultiValuedMap.transformingMap(new ArrayListValuedHashMap<K, V>(),
+        return TransformedMultiValuedMap.transformingMap(new ArrayListValuedHashMap<>(),
                 TransformerUtils.<K>nopTransformer(), TransformerUtils.<V>nopTransformer());
     }
 
@@ -58,7 +58,7 @@ public void testKeyTransformedMap() {
         final Object[] els = { "1", "3", "5", "7", "2", "4", "6" };
 
         final MultiValuedMap<K, V> map = TransformedMultiValuedMap.transformingMap(
-                new ArrayListValuedHashMap<K, V>(),
+                new ArrayListValuedHashMap<>(),
                 (Transformer<? super K, ? extends K>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER,
                 null);
         assertEquals(0, map.size());
@@ -83,7 +83,7 @@ public void testValueTransformedMap() {
         final Object[] els = { "1", "3", "5", "7", "2", "4", "6" };
 
         final MultiValuedMap<K, V> map = TransformedMultiValuedMap.transformingMap(
-                new ArrayListValuedHashMap<K, V>(), null,
+                new ArrayListValuedHashMap<>(), null,
                 (Transformer<? super V, ? extends V>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, map.size());
         for (int i = 0; i < els.length; i++) {
diff --git a/src/test/java/org/apache/commons/collections4/multimap/UnmodifiableMultiValuedMapTest.java b/src/test/java/org/apache/commons/collections4/multimap/UnmodifiableMultiValuedMapTest.java
index 31c8e02002..d9d4b954d6 100644
--- a/src/test/java/org/apache/commons/collections4/multimap/UnmodifiableMultiValuedMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/multimap/UnmodifiableMultiValuedMapTest.java
@@ -71,7 +71,7 @@ public boolean isRemoveSupported() {
     @Override
     public MultiValuedMap<K, V> makeObject() {
         return UnmodifiableMultiValuedMap.<K, V>unmodifiableMultiValuedMap(
-                new ArrayListValuedHashMap<K, V>());
+                new ArrayListValuedHashMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/multiset/PredicatedMultiSetTest.java b/src/test/java/org/apache/commons/collections4/multiset/PredicatedMultiSetTest.java
index c7e2523f90..3f4a5bcac7 100644
--- a/src/test/java/org/apache/commons/collections4/multiset/PredicatedMultiSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/multiset/PredicatedMultiSetTest.java
@@ -52,11 +52,11 @@ protected MultiSet<T> decorateMultiSet(final HashMultiSet<T> multiset, final Pre
 
     @Override
     public MultiSet<T> makeObject() {
-        return decorateMultiSet(new HashMultiSet<T>(), truePredicate);
+        return decorateMultiSet(new HashMultiSet<>(), truePredicate);
     }
 
     protected MultiSet<T> makeTestMultiSet() {
-        return decorateMultiSet(new HashMultiSet<T>(), stringPredicate());
+        return decorateMultiSet(new HashMultiSet<>(), stringPredicate());
     }
 
     @Override
@@ -103,7 +103,7 @@ public void testIllegalDecorate() {
         elements.add("four");
         assertThrows(IllegalArgumentException.class, () -> decorateMultiSet((HashMultiSet<T>) elements, stringPredicate()),
                 "MultiSet contains an element that should fail the predicate.");
-        assertThrows(NullPointerException.class, () -> decorateMultiSet(new HashMultiSet<T>(), null),
+        assertThrows(NullPointerException.class, () -> decorateMultiSet(new HashMultiSet<>(), null),
                 "Expecting NullPointerException for null predicate.");
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/multiset/SynchronizedMultiSetTest.java b/src/test/java/org/apache/commons/collections4/multiset/SynchronizedMultiSetTest.java
index 1349aab932..0e8906c72b 100644
--- a/src/test/java/org/apache/commons/collections4/multiset/SynchronizedMultiSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/multiset/SynchronizedMultiSetTest.java
@@ -32,7 +32,7 @@ public SynchronizedMultiSetTest() {
 
     @Override
     public MultiSet<T> makeObject() {
-        return SynchronizedMultiSet.synchronizedMultiSet(new HashMultiSet<T>());
+        return SynchronizedMultiSet.synchronizedMultiSet(new HashMultiSet<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/multiset/UnmodifiableMultiSetTest.java b/src/test/java/org/apache/commons/collections4/multiset/UnmodifiableMultiSetTest.java
index a3810422e3..162b662fab 100644
--- a/src/test/java/org/apache/commons/collections4/multiset/UnmodifiableMultiSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/multiset/UnmodifiableMultiSetTest.java
@@ -40,7 +40,7 @@ public UnmodifiableMultiSetTest() {
 
     @Override
     public MultiSet<E> makeObject() {
-        return UnmodifiableMultiSet.unmodifiableMultiSet(new HashMultiSet<E>());
+        return UnmodifiableMultiSet.unmodifiableMultiSet(new HashMultiSet<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/queue/PredicatedQueueTest.java b/src/test/java/org/apache/commons/collections4/queue/PredicatedQueueTest.java
index 9ec51c6aa8..46ee5413b2 100644
--- a/src/test/java/org/apache/commons/collections4/queue/PredicatedQueueTest.java
+++ b/src/test/java/org/apache/commons/collections4/queue/PredicatedQueueTest.java
@@ -50,7 +50,7 @@ protected Queue<E> decorateCollection(final Queue<E> queue, final Predicate<E> p
 
     @Override
     public Queue<E> makeObject() {
-        return decorateCollection(new LinkedList<E>(), truePredicate);
+        return decorateCollection(new LinkedList<>(), truePredicate);
     }
 
     @Override
@@ -73,7 +73,7 @@ public Collection<E> makeConfirmedFullCollection() {
     protected Predicate<E> testPredicate = o -> o instanceof String;
 
     public Queue<E> makeTestQueue() {
-        return decorateCollection(new LinkedList<E>(), testPredicate);
+        return decorateCollection(new LinkedList<>(), testPredicate);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/queue/SynchronizedQueueTest.java b/src/test/java/org/apache/commons/collections4/queue/SynchronizedQueueTest.java
index 00b7904617..8114b9d882 100644
--- a/src/test/java/org/apache/commons/collections4/queue/SynchronizedQueueTest.java
+++ b/src/test/java/org/apache/commons/collections4/queue/SynchronizedQueueTest.java
@@ -41,7 +41,7 @@ public String getCompatibilityVersion() {
 
     @Override
     public Queue<T> makeObject() {
-        return SynchronizedQueue.synchronizedQueue(new LinkedList<T>());
+        return SynchronizedQueue.synchronizedQueue(new LinkedList<>());
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/queue/TransformedQueueTest.java b/src/test/java/org/apache/commons/collections4/queue/TransformedQueueTest.java
index 6f9ec4065a..63fd424526 100644
--- a/src/test/java/org/apache/commons/collections4/queue/TransformedQueueTest.java
+++ b/src/test/java/org/apache/commons/collections4/queue/TransformedQueueTest.java
@@ -55,7 +55,7 @@ public Queue<E> makeConfirmedFullCollection() {
     @Override
     @SuppressWarnings("unchecked")
     public Queue<E> makeObject() {
-        return TransformedQueue.transformingQueue(new LinkedList<E>(),
+        return TransformedQueue.transformingQueue(new LinkedList<>(),
                 (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/queue/UnmodifiableQueueTest.java b/src/test/java/org/apache/commons/collections4/queue/UnmodifiableQueueTest.java
index 96ec176c26..8b213ed433 100644
--- a/src/test/java/org/apache/commons/collections4/queue/UnmodifiableQueueTest.java
+++ b/src/test/java/org/apache/commons/collections4/queue/UnmodifiableQueueTest.java
@@ -43,7 +43,7 @@ public UnmodifiableQueueTest() {
 
     @Override
     public Queue<E> makeObject() {
-        return UnmodifiableQueue.unmodifiableQueue(new LinkedList<E>());
+        return UnmodifiableQueue.unmodifiableQueue(new LinkedList<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/sequence/SequencesComparatorTest.java b/src/test/java/org/apache/commons/collections4/sequence/SequencesComparatorTest.java
index 9d27467761..97c8143ef7 100644
--- a/src/test/java/org/apache/commons/collections4/sequence/SequencesComparatorTest.java
+++ b/src/test/java/org/apache/commons/collections4/sequence/SequencesComparatorTest.java
@@ -118,7 +118,7 @@ public void testShadok() {
         List<List<String>> shadokSentences = new ArrayList<>();
         for (int lg=0; lg<lgMax; ++lg) {
             final List<List<String>> newTab = new ArrayList<>();
-            newTab.add(new ArrayList<String>());
+            newTab.add(new ArrayList<>());
             for (final String element : shadokAlph) {
                 for (final List<String> sentence : shadokSentences) {
                     final List<String> newSentence = new ArrayList<>(sentence);
diff --git a/src/test/java/org/apache/commons/collections4/set/ListOrderedSetTest.java b/src/test/java/org/apache/commons/collections4/set/ListOrderedSetTest.java
index ae47a2142c..77d80e2822 100644
--- a/src/test/java/org/apache/commons/collections4/set/ListOrderedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/ListOrderedSetTest.java
@@ -55,7 +55,7 @@ public ListOrderedSetTest() {
 
     @Override
     public ListOrderedSet<E> makeObject() {
-        return ListOrderedSet.listOrderedSet(new HashSet<E>());
+        return ListOrderedSet.listOrderedSet(new HashSet<>());
     }
 
     @SuppressWarnings("unchecked")
@@ -267,8 +267,8 @@ public void testDecorator() {
                 () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet((List<E>) null)),
                 () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet((Set<E>) null)),
                 () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet(null, null)),
-                () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet(new HashSet<E>(), null)),
-                () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet(null, new ArrayList<E>()))
+                () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet(new HashSet<>(), null)),
+                () -> assertThrows(NullPointerException.class, () -> ListOrderedSet.listOrderedSet(null, new ArrayList<>()))
         );
     }
 
diff --git a/src/test/java/org/apache/commons/collections4/set/MapBackedSet2Test.java b/src/test/java/org/apache/commons/collections4/set/MapBackedSet2Test.java
index ce6497b37a..524b93eef3 100644
--- a/src/test/java/org/apache/commons/collections4/set/MapBackedSet2Test.java
+++ b/src/test/java/org/apache/commons/collections4/set/MapBackedSet2Test.java
@@ -38,7 +38,7 @@ public MapBackedSet2Test() {
 
     @Override
     public Set<E> makeObject() {
-        return MapBackedSet.mapBackedSet(new LinkedMap<E, Object>());
+        return MapBackedSet.mapBackedSet(new LinkedMap<>());
     }
 
     @SuppressWarnings("unchecked")
diff --git a/src/test/java/org/apache/commons/collections4/set/MapBackedSetTest.java b/src/test/java/org/apache/commons/collections4/set/MapBackedSetTest.java
index d9f720704f..660272beff 100644
--- a/src/test/java/org/apache/commons/collections4/set/MapBackedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/MapBackedSetTest.java
@@ -33,7 +33,7 @@ public MapBackedSetTest() {
 
     @Override
     public Set<E> makeObject() {
-        return MapBackedSet.mapBackedSet(new HashedMap<E, Object>());
+        return MapBackedSet.mapBackedSet(new HashedMap<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/set/PredicatedNavigableSetTest.java b/src/test/java/org/apache/commons/collections4/set/PredicatedNavigableSetTest.java
index 8e32f1510a..52ed7974fd 100644
--- a/src/test/java/org/apache/commons/collections4/set/PredicatedNavigableSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/PredicatedNavigableSetTest.java
@@ -47,7 +47,7 @@ public PredicatedNavigableSetTest() {
 
     @Override
     public NavigableSet<E> makeObject() {
-        return PredicatedNavigableSet.predicatedNavigableSet(new TreeSet<E>(), truePredicate);
+        return PredicatedNavigableSet.predicatedNavigableSet(new TreeSet<>(), truePredicate);
     }
 
     @Override
@@ -60,7 +60,7 @@ public NavigableSet<E> makeFullCollection() {
         o -> o instanceof String && ((String) o).startsWith("A");
 
     protected PredicatedNavigableSet<E> makeTestSet() {
-        return PredicatedNavigableSet.predicatedNavigableSet(new TreeSet<E>(), testPredicate);
+        return PredicatedNavigableSet.predicatedNavigableSet(new TreeSet<>(), testPredicate);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/set/PredicatedSetTest.java b/src/test/java/org/apache/commons/collections4/set/PredicatedSetTest.java
index e7722e4770..afba189e22 100644
--- a/src/test/java/org/apache/commons/collections4/set/PredicatedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/PredicatedSetTest.java
@@ -47,7 +47,7 @@ protected PredicatedSet<E> decorateSet(final Set<E> set, final Predicate<? super
 
     @Override
     public PredicatedSet<E> makeObject() {
-        return decorateSet(new HashSet<E>(), truePredicate);
+        return decorateSet(new HashSet<>(), truePredicate);
     }
 
     @Override
@@ -60,7 +60,7 @@ public E[] getFullElements() {
         o -> o instanceof String;
 
     protected PredicatedSet<E> makeTestSet() {
-        return decorateSet(new HashSet<E>(), testPredicate);
+        return decorateSet(new HashSet<>(), testPredicate);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/set/PredicatedSortedSetTest.java b/src/test/java/org/apache/commons/collections4/set/PredicatedSortedSetTest.java
index d5676ef7d2..a5e5df3f89 100644
--- a/src/test/java/org/apache/commons/collections4/set/PredicatedSortedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/PredicatedSortedSetTest.java
@@ -47,7 +47,7 @@ public PredicatedSortedSetTest() {
 
     @Override
     public SortedSet<E> makeObject() {
-        return PredicatedSortedSet.predicatedSortedSet(new TreeSet<E>(), truePredicate);
+        return PredicatedSortedSet.predicatedSortedSet(new TreeSet<>(), truePredicate);
     }
 
     @Override
@@ -60,7 +60,7 @@ public SortedSet<E> makeFullCollection() {
         o -> o instanceof String && ((String) o).startsWith("A");
 
     protected PredicatedSortedSet<E> makeTestSet() {
-        return PredicatedSortedSet.predicatedSortedSet(new TreeSet<E>(), testPredicate);
+        return PredicatedSortedSet.predicatedSortedSet(new TreeSet<>(), testPredicate);
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/set/TransformedNavigableSetTest.java b/src/test/java/org/apache/commons/collections4/set/TransformedNavigableSetTest.java
index d2c8e04558..7734198e14 100644
--- a/src/test/java/org/apache/commons/collections4/set/TransformedNavigableSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/TransformedNavigableSetTest.java
@@ -44,7 +44,7 @@ public TransformedNavigableSetTest() {
     @Override
     @SuppressWarnings("unchecked")
     public NavigableSet<E> makeObject() {
-        return TransformedNavigableSet.transformingNavigableSet(new TreeSet<E>(),
+        return TransformedNavigableSet.transformingNavigableSet(new TreeSet<>(),
                 (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
@@ -59,7 +59,7 @@ public NavigableSet<E> makeFullCollection() {
     @Test
     @SuppressWarnings("unchecked")
     public void testTransformedSet() {
-        final NavigableSet<E> set = TransformedNavigableSet.transformingNavigableSet(new TreeSet<E>(),
+        final NavigableSet<E> set = TransformedNavigableSet.transformingNavigableSet(new TreeSet<>(),
                 (Transformer<E, E>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, set.size());
         final E[] els = (E[]) new Object[] { "1", "3", "5", "7", "2", "4", "6" };
diff --git a/src/test/java/org/apache/commons/collections4/set/TransformedSetTest.java b/src/test/java/org/apache/commons/collections4/set/TransformedSetTest.java
index 2708310743..05b4791ccd 100644
--- a/src/test/java/org/apache/commons/collections4/set/TransformedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/TransformedSetTest.java
@@ -54,7 +54,7 @@ public Set<E> makeConfirmedFullCollection() {
     @Override
     @SuppressWarnings("unchecked")
     public Set<E> makeObject() {
-        return TransformedSet.transformingSet(new HashSet<E>(),
+        return TransformedSet.transformingSet(new HashSet<>(),
                 (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
@@ -69,7 +69,7 @@ public Set<E> makeFullCollection() {
     @Test
     @SuppressWarnings("unchecked")
     public void testTransformedSet() {
-        final Set<E> set = TransformedSet.transformingSet(new HashSet<E>(),
+        final Set<E> set = TransformedSet.transformingSet(new HashSet<>(),
                 (Transformer<E, E>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, set.size());
         final E[] els = (E[]) new Object[] { "1", "3", "5", "7", "2", "4", "6" };
diff --git a/src/test/java/org/apache/commons/collections4/set/TransformedSortedSetTest.java b/src/test/java/org/apache/commons/collections4/set/TransformedSortedSetTest.java
index 8593ead4fe..faaf6ddecf 100644
--- a/src/test/java/org/apache/commons/collections4/set/TransformedSortedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/TransformedSortedSetTest.java
@@ -44,7 +44,7 @@ public TransformedSortedSetTest() {
     @Override
     @SuppressWarnings("unchecked")
     public SortedSet<E> makeObject() {
-        return TransformedSortedSet.transformingSortedSet(new TreeSet<E>(), (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
+        return TransformedSortedSet.transformingSortedSet(new TreeSet<>(), (Transformer<E, E>) TransformedCollectionTest.NOOP_TRANSFORMER);
     }
 
     @Override
@@ -57,7 +57,7 @@ public SortedSet<E> makeFullCollection() {
     @Test
     @SuppressWarnings("unchecked")
     public void testTransformedSet() {
-        final SortedSet<E> set = TransformedSortedSet.transformingSortedSet(new TreeSet<E>(),
+        final SortedSet<E> set = TransformedSortedSet.transformingSortedSet(new TreeSet<>(),
                 (Transformer<E, E>) TransformedCollectionTest.STRING_TO_INTEGER_TRANSFORMER);
         assertEquals(0, set.size());
         final E[] els = (E[]) new Object[] { "1", "3", "5", "7", "2", "4", "6" };
diff --git a/src/test/java/org/apache/commons/collections4/set/UnmodifiableSetTest.java b/src/test/java/org/apache/commons/collections4/set/UnmodifiableSetTest.java
index 93bff22ab4..42daccfea1 100644
--- a/src/test/java/org/apache/commons/collections4/set/UnmodifiableSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/UnmodifiableSetTest.java
@@ -41,7 +41,7 @@ public UnmodifiableSetTest() {
 
     @Override
     public Set<E> makeObject() {
-        return UnmodifiableSet.unmodifiableSet(new HashSet<E>());
+        return UnmodifiableSet.unmodifiableSet(new HashSet<>());
     }
 
     @Override
diff --git a/src/test/java/org/apache/commons/collections4/set/UnmodifiableSortedSetTest.java b/src/test/java/org/apache/commons/collections4/set/UnmodifiableSortedSetTest.java
index 2a51ae1d0e..258e210977 100644
--- a/src/test/java/org/apache/commons/collections4/set/UnmodifiableSortedSetTest.java
+++ b/src/test/java/org/apache/commons/collections4/set/UnmodifiableSortedSetTest.java
@@ -46,7 +46,7 @@ public UnmodifiableSortedSetTest() {
 
     @Override
     public SortedSet<E> makeObject() {
-        return UnmodifiableSortedSet.unmodifiableSortedSet(new TreeSet<E>());
+        return UnmodifiableSortedSet.unmodifiableSortedSet(new TreeSet<>());
     }
 
     @Override
@@ -101,7 +101,7 @@ public void verifyUnmodifiable(final Set<E> set) {
         assertAll(
                 () -> assertThrows(UnsupportedOperationException.class, () -> set.add((E) "value"),
                         "Expecting UnsupportedOperationException."),
-                () -> assertThrows(UnsupportedOperationException.class, () -> set.addAll(new TreeSet<E>()),
+                () -> assertThrows(UnsupportedOperationException.class, () -> set.addAll(new TreeSet<>()),
                         "Expecting UnsupportedOperationException."),
                 () -> assertThrows(UnsupportedOperationException.class, () -> set.clear(),
                         "Expecting UnsupportedOperationException."),
diff --git a/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java b/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java
index 70e43b6441..a2458a3d5f 100644
--- a/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java
+++ b/src/test/java/org/apache/commons/collections4/splitmap/TransformedSplitMapTest.java
@@ -54,7 +54,7 @@ public TransformedSplitMapTest() {
     @Test
     public void testTransformedMap() {
         final TransformedSplitMap<Integer, String, Object, Class<?>> map = TransformedSplitMap.transformingMap(
-                new HashMap<String, Class<?>>(), intToString, objectToClass);
+                new HashMap<>(), intToString, objectToClass);
 
         final Integer[] k = { 0, 1, 2, 3, 4, 5, 6 };
         final Object[] v = { "", new Object(), new HashMap<>(), 0, BigInteger.TEN, null,
@@ -78,7 +78,7 @@ public void testTransformedMap() {
         assertEquals(--sz, map.size());
 
         final TransformedSplitMap<String, String, String, Integer> map2 = TransformedSplitMap.transformingMap(
-                new HashMap<String, Integer>(), NOPTransformer.<String>nopTransformer(), stringToInt);
+                new HashMap<>(), NOPTransformer.<String>nopTransformer(), stringToInt);
         assertEquals(0, map2.size());
         for (int i = 0; i < 6; i++) {
             map2.put(String.valueOf(i), String.valueOf(i));
@@ -97,7 +97,7 @@ public void testTransformedMap() {
     @Test
     public void testMapIterator() {
         final TransformedSplitMap<String, String, String, Integer> map =
-                TransformedSplitMap.transformingMap(new HashMap<String, Integer>(),
+                TransformedSplitMap.transformingMap(new HashMap<>(),
                                                     NOPTransformer.<String>nopTransformer(), stringToInt);
         assertEquals(0, map.size());
         for (int i = 0; i < 6; i++) {
@@ -114,7 +114,7 @@ public void testMapIterator() {
     @Test
     public void testEmptyMap() throws IOException, ClassNotFoundException {
         final TransformedSplitMap<String, String, String, String> map =
-                TransformedSplitMap.transformingMap(new HashMap<String, String>(),
+                TransformedSplitMap.transformingMap(new HashMap<>(),
                                                     NOPTransformer.<String>nopTransformer(),
                                                     NOPTransformer.<String>nopTransformer() );
 
@@ -131,7 +131,7 @@ public void testEmptyMap() throws IOException, ClassNotFoundException {
     @Test
     public void testFullMap() throws IOException, ClassNotFoundException {
         final TransformedSplitMap<String, String, String, String> map = TransformedSplitMap.transformingMap(
-                new HashMap<String, String>(),
+                new HashMap<>(),
                 NOPTransformer.<String>nopTransformer(),
                 NOPTransformer.<String>nopTransformer() );
         map.put( "a", "b" );
diff --git a/src/test/java/org/apache/commons/collections4/trie/PatriciaTrieTest.java b/src/test/java/org/apache/commons/collections4/trie/PatriciaTrieTest.java
index 06a208ca62..06a6dc7c01 100755
--- a/src/test/java/org/apache/commons/collections4/trie/PatriciaTrieTest.java
+++ b/src/test/java/org/apache/commons/collections4/trie/PatriciaTrieTest.java
@@ -400,15 +400,15 @@ public void testPrefixMapClear() {
     public void testPrefixMapClearNothing() {
         final Trie<String, Integer> trie = new PatriciaTrie<>();
         final SortedMap<String, Integer> prefixMap = trie.prefixMap("And");
-        assertEquals(new HashSet<String>(), prefixMap.keySet());
-        assertEquals(new ArrayList<Integer>(0), new ArrayList<>(prefixMap.values()));
+        assertEquals(new HashSet<>(), prefixMap.keySet());
+        assertEquals(new ArrayList<>(0), new ArrayList<>(prefixMap.values()));
 
         prefixMap.clear();
         assertTrue(prefixMap.isEmpty());
         assertTrue(prefixMap.isEmpty());
         assertTrue(prefixMap.isEmpty());
-        assertEquals(new HashSet<String>(), trie.keySet());
-        assertEquals(new ArrayList<Integer>(0), new ArrayList<>(trie.values()));
+        assertEquals(new HashSet<>(), trie.keySet());
+        assertEquals(new ArrayList<>(0), new ArrayList<>(trie.values()));
     }
 
     @Test
diff --git a/src/test/java/org/apache/commons/collections4/trie/UnmodifiableTrieTest.java b/src/test/java/org/apache/commons/collections4/trie/UnmodifiableTrieTest.java
index db3bf3afaa..d09e27bd7b 100644
--- a/src/test/java/org/apache/commons/collections4/trie/UnmodifiableTrieTest.java
+++ b/src/test/java/org/apache/commons/collections4/trie/UnmodifiableTrieTest.java
@@ -39,7 +39,7 @@ public UnmodifiableTrieTest() {
 
     @Override
     public Trie<String, V> makeObject() {
-        return UnmodifiableTrie.unmodifiableTrie(new PatriciaTrie<V>());
+        return UnmodifiableTrie.unmodifiableTrie(new PatriciaTrie<>());
     }
 
     @Override