diff --git a/src/main/java/org/apache/commons/collections4/iterators/PairingIterator.java b/src/main/java/org/apache/commons/collections4/iterators/PairingIterator.java
new file mode 100644
index 0000000000..4b95884ef5
--- /dev/null
+++ b/src/main/java/org/apache/commons/collections4/iterators/PairingIterator.java
@@ -0,0 +1,166 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.collections4.iterators;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Objects;
+import org.apache.commons.collections4.iterators.PairingIterator.Entry;
+
+/**
+ * Provides an iteration over the elements of two iterators. It will be return a
+ * {@link Entry} containing the child iterators elements.
+ *
+ * Given two {@link Iterator} instances {@code A} and {@code B}. The
+ * {@link #next()} method will return a {@link Entry} with the elements of the
+ * {@code A} and {@code B} as values of the {@link Entry} until both iterators
+ * are exhausted.
+ *
+ *
+ * If one of the iterators is null, the result {@link Entry} contains also a
+ * null values until both child iterators exhausted.
+ *
+ *
+ * If one iterator has more elements then the other, the result {@link Entry}
+ * will contain a null value and the value of the not empty child iterator until
+ * both of the iterator exhausted.
+ *
+ * @param type of first value. The first value of {@link Entry}
+ *
+ * @param type of second value. The second value of {@link Entry}
+ *
+ * @since 4.4
+ */
+public class PairingIterator implements Iterator> {
+
+ private final Iterator firstIterator;
+ private final Iterator secondIterator;
+
+ /**
+ * Constructs a new PairingIterator
that will provide a
+ * {@link Entry} containing the child iterator elements.
+ *
+ * @param firstIterator the first iterator
+ * @param secondIterator the second iterator
+ */
+ public PairingIterator(Iterator firstIterator, Iterator secondIterator) {
+ this.firstIterator = firstIterator;
+ this.secondIterator = secondIterator;
+ }
+
+ /**
+ * Returns {@code true} if one of the child iterators has remaining elements.
+ */
+ @Override
+ public boolean hasNext() {
+ return (null != firstIterator && firstIterator.hasNext())
+ || (null != secondIterator && secondIterator.hasNext());
+ }
+
+ /**
+ * Returns the next {@link Entry} with the next values of the child iterators.
+ *
+ * @return a {@link Entry} with the next values of child iterators
+ * @throws NoSuchElementException if no child iterator has any more elements
+ */
+ @Override
+ public Entry next() throws NoSuchElementException {
+ if (!hasNext()) {
+ throw new NoSuchElementException();
+ }
+ final F firstValue = null != firstIterator && firstIterator.hasNext() ? firstIterator.next() : null;
+ final S secondValue = null != secondIterator && secondIterator.hasNext() ? secondIterator.next() : null;
+ return new Entry(firstValue, secondValue);
+ }
+
+ /**
+ * Removes the last returned values of the child iterators.
+ */
+ @Override
+ public void remove() {
+ if (firstIterator != null) {
+ firstIterator.remove();
+ }
+ if (secondIterator != null) {
+ secondIterator.remove();
+ }
+ }
+
+ /**
+ * Contains two values of different generic types.
+ *
+ * @param the type of the first element
+ * @param the type of the second element
+ */
+ public static class Entry {
+ private final F firstValue;
+ private final S secondValue;
+
+ /**
+ * Constructs a new {@link Entry} of two generic values.
+ *
+ * @param firstValue the first value
+ * @param secondValue the second value
+ */
+ Entry(F firstValue, S secondValue) {
+ this.firstValue = firstValue;
+ this.secondValue = secondValue;
+ }
+
+ /**
+ * Returns the first value.
+ *
+ * @return the first value
+ */
+ public F getFirstValue() {
+ return firstValue;
+ }
+
+ /**
+ * Returns the second value.
+ *
+ * @return the second value
+ */
+ public S getSecondValue() {
+ return secondValue;
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(firstValue, secondValue);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj)
+ return true;
+ if (obj == null)
+ return false;
+ if (getClass() != obj.getClass())
+ return false;
+ Entry other = (Entry) obj;
+ return Objects.equals(firstValue, other.firstValue) && Objects.equals(secondValue, other.secondValue);
+ }
+
+ @Override
+ public String toString() {
+ return "Entry [firstValue=" + firstValue + ", secondValue=" + secondValue + "]";
+ }
+
+ }
+
+}
diff --git a/src/test/java/org/apache/commons/collections4/iterators/PairingIteratorTest.java b/src/test/java/org/apache/commons/collections4/iterators/PairingIteratorTest.java
new file mode 100644
index 0000000000..8c1d188909
--- /dev/null
+++ b/src/test/java/org/apache/commons/collections4/iterators/PairingIteratorTest.java
@@ -0,0 +1,271 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.commons.collections4.iterators;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+import org.apache.commons.collections4.IteratorUtils;
+import org.apache.commons.collections4.iterators.PairingIterator.Entry;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Unit test suite for {@link PairingIterator}.
+ *
+ */
+public class PairingIteratorTest extends AbstractIteratorTest> {
+
+ public PairingIteratorTest(String testName) {
+ super(testName);
+ }
+
+ @Test
+ public void testNullValuesBoth() {
+ final PairingIterator pairingIterator = new PairingIterator<>(null, null);
+
+ Assert.assertFalse(pairingIterator.hasNext());
+ try {
+ pairingIterator.next();
+ fail();
+
+ } catch (NoSuchElementException e) {
+ Assert.assertNotNull(e);
+ }
+ }
+
+ @Test
+ public void testNullValueFirst() {
+ final List firstList = Arrays.asList(new String[] { "A" });
+ final PairingIterator pairingIterator = new PairingIterator<>(null, firstList.iterator());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ Entry next = pairingIterator.next();
+ Assert.assertEquals(null, next.getFirstValue());
+ Assert.assertEquals("A", next.getSecondValue());
+ }
+
+ @Test
+ public void testNullValueSecond() {
+ final List firstList = Arrays.asList(new String[] { "A" });
+ final PairingIterator pairingIterator = new PairingIterator<>(firstList.iterator(), null);
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ Entry next = pairingIterator.next();
+ Assert.assertEquals("A", next.getFirstValue());
+ Assert.assertEquals(null, next.getSecondValue());
+ }
+
+ @Test
+ public void testTwoIteratorsWithBothTwoElements() {
+ final List firstList = Arrays.asList(new String[] { "A1", "A2" });
+ final List secondList = Arrays.asList(new String[] { "B1", "B2" });
+ final PairingIterator pairingIterator = new PairingIterator<>(firstList.iterator(),
+ secondList.iterator());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ Entry next = pairingIterator.next();
+ Assert.assertEquals("A1", next.getFirstValue());
+ Assert.assertEquals("B1", next.getSecondValue());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+ next = pairingIterator.next();
+ Assert.assertEquals("A2", next.getFirstValue());
+ Assert.assertEquals("B2", next.getSecondValue());
+
+ Assert.assertFalse(pairingIterator.hasNext());
+ }
+
+ @Test
+ public void testTwoIteratorsWithDifferentSize() {
+ final List firstList = Arrays.asList(new String[] { "A1", "A2", "A3" });
+ final List secondList = Arrays.asList(new String[] { "B1", "B2" });
+ final PairingIterator pairingIterator = new PairingIterator<>(firstList.iterator(),
+ secondList.iterator());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ Entry next = pairingIterator.next();
+ Assert.assertEquals("A1", next.getFirstValue());
+ Assert.assertEquals("B1", next.getSecondValue());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ next = pairingIterator.next();
+ Assert.assertEquals("A2", next.getFirstValue());
+ Assert.assertEquals("B2", next.getSecondValue());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+ next = pairingIterator.next();
+ Assert.assertEquals("A3", next.getFirstValue());
+ Assert.assertEquals(null, next.getSecondValue());
+
+ Assert.assertFalse(pairingIterator.hasNext());
+ }
+
+ @Test
+ public void testTwoIteratorsWithDifferentSize2() {
+ final List firstList = Arrays.asList(new String[] { "A1", });
+ final List secondList = Arrays.asList(new String[] { "B1", "B2" });
+ final PairingIterator pairingIterator = new PairingIterator<>(firstList.iterator(),
+ secondList.iterator());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ Entry next = pairingIterator.next();
+ Assert.assertEquals("A1", next.getFirstValue());
+ Assert.assertEquals("B1", next.getSecondValue());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ next = pairingIterator.next();
+ Assert.assertEquals(null, next.getFirstValue());
+ Assert.assertEquals("B2", next.getSecondValue());
+
+ Assert.assertFalse(pairingIterator.hasNext());
+ }
+
+ @Test
+ public void testTwoIteratorsWithNullValues() {
+ final List firstList = Arrays.asList(new String[] { null, "A2" });
+ final List secondList = Arrays.asList(new String[] { "B1", null });
+ final PairingIterator pairingIterator = new PairingIterator<>(firstList.iterator(),
+ secondList.iterator());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+
+ Entry next = pairingIterator.next();
+ Assert.assertEquals(null, next.getFirstValue());
+ Assert.assertEquals("B1", next.getSecondValue());
+
+ Assert.assertTrue(pairingIterator.hasNext());
+ next = pairingIterator.next();
+ Assert.assertEquals("A2", next.getFirstValue());
+ Assert.assertEquals(null, next.getSecondValue());
+
+ Assert.assertFalse(pairingIterator.hasNext());
+ }
+
+ @Test
+ public void testRemoveWithOneNullIterator() {
+ final List firstList = new ArrayList<>();
+ firstList.add("A1");
+ final Iterator leftIterator = firstList.iterator();
+ final PairingIterator pairingIterator = new PairingIterator<>(leftIterator, null);
+
+ pairingIterator.next();
+ pairingIterator.remove();
+ Assert.assertTrue(firstList.isEmpty());
+ }
+
+ @Test
+ public void testRemoveWithOneNullIterator2() {
+ final List secondList = new ArrayList<>();
+ secondList.add("A1");
+ final Iterator rightIterator = secondList.iterator();
+ final PairingIterator pairingIterator = new PairingIterator<>(null, rightIterator);
+
+ pairingIterator.next();
+ pairingIterator.remove();
+ Assert.assertTrue(secondList.isEmpty());
+ }
+
+ @Test
+ public void testEntryEquals_notEquals() {
+ final String firstValue = "A";
+ final String secondValue = "B";
+ final Entry entry1 = new Entry<>(firstValue, secondValue);
+ final Entry entry2 = new Entry<>(secondValue, firstValue);
+
+ Assert.assertNotEquals(entry1, entry2);
+ }
+
+ @Test
+ public void testEntryEquals_equals() {
+ final String firstValue = "A";
+ final String secondValue = "A";
+ final Entry entry1 = new Entry<>(firstValue, secondValue);
+ final Entry entry2 = new Entry<>(secondValue, firstValue);
+
+ Assert.assertEquals(entry1, entry2);
+ }
+
+ @Test
+ public void testEntryEquals_equalsSameInstance() {
+ final String firstValue = "A";
+ final String secondValue = "A";
+ final Entry entry1 = new Entry<>(firstValue, secondValue);
+
+ Assert.assertEquals(entry1, entry1);
+ }
+
+ @Test
+ public void testEntryEquals_null() {
+ final String firstValue = "A";
+ final String secondValue = "A";
+ final Entry entry1 = new Entry<>(firstValue, secondValue);
+
+ Assert.assertNotEquals(entry1, null);
+ }
+
+ @Test
+ public void testEntryEquals_differentClasses() {
+ final String firstValue = "A";
+ final String secondValue = "A";
+ final Entry entry1 = new Entry<>(firstValue, secondValue);
+
+ Assert.assertNotEquals(entry1, "");
+ }
+
+ @Test
+ public void testEntryToString() {
+ final String firstValue = "A";
+ final String secondValue = "A";
+ final Entry entry = new Entry<>(firstValue, secondValue);
+
+ String string = entry.toString();
+ Assert.assertTrue(string.contains(firstValue));
+ Assert.assertTrue(string.contains(secondValue));
+
+ }
+
+ @Override
+ public Iterator> makeEmptyIterator() {
+ return new PairingIterator(IteratorUtils.emptyIterator(),
+ IteratorUtils.emptyIterator());
+ }
+
+ @Override
+ public Iterator> makeObject() {
+ final List firstList = new ArrayList<>();
+ firstList.add("A1");
+ firstList.add("A2");
+ firstList.add("A3");
+ final List secondList = new ArrayList<>();
+ secondList.add("B1");
+ secondList.add("B2");
+ return new PairingIterator<>(firstList.iterator(), secondList.iterator());
+ }
+
+}