diff --git a/2.1.06-Exercise-LoadA9Patch/build.gradle b/2.1.06-Exercise-LoadA9Patch/build.gradle
index 105f655..c796eef 100644
--- a/2.1.06-Exercise-LoadA9Patch/build.gradle
+++ b/2.1.06-Exercise-LoadA9Patch/build.gradle
@@ -6,7 +6,7 @@ buildscript {
     }
     dependencies {
         classpath 'de.richsource.gradle.plugins:gwt-gradle-plugin:0.6'
-        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.android.tools.build:gradle:2.3.3'
         classpath 'org.robovm:robovm-gradle-plugin:1.8.0'
     }
 }
diff --git a/2.1.06-Exercise-LoadA9Patch/core/src/com/udacity/gamedev/ninepatch/NinePatchDemo.java b/2.1.06-Exercise-LoadA9Patch/core/src/com/udacity/gamedev/ninepatch/NinePatchDemo.java
index 4400197..c815b05 100644
--- a/2.1.06-Exercise-LoadA9Patch/core/src/com/udacity/gamedev/ninepatch/NinePatchDemo.java
+++ b/2.1.06-Exercise-LoadA9Patch/core/src/com/udacity/gamedev/ninepatch/NinePatchDemo.java
@@ -13,8 +13,8 @@ public class NinePatchDemo extends ApplicationAdapter {
     private static final float TEST_SIZE_1 = 20;
     private static final float TEST_SIZE_2 = 40;
 
-    SpriteBatch batch;
-    FitViewport viewport;
+    private SpriteBatch batch;
+    private FitViewport viewport;
 
     // TODO: Add a Texture for the raw platform image
 
diff --git a/2.1.07-Exercise-Animations/build.gradle b/2.1.07-Exercise-Animations/build.gradle
index 832d14d..e92174c 100644
--- a/2.1.07-Exercise-Animations/build.gradle
+++ b/2.1.07-Exercise-Animations/build.gradle
@@ -6,7 +6,7 @@ buildscript {
     }
     dependencies {
         classpath 'de.richsource.gradle.plugins:gwt-gradle-plugin:0.6'
-        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.android.tools.build:gradle:2.3.3'
         classpath 'org.robovm:robovm-gradle-plugin:1.8.0'
     }
 }
diff --git a/2.1.07-Exercise-Animations/core/src/com/udacity/gamedev/animations/Animations.java b/2.1.07-Exercise-Animations/core/src/com/udacity/gamedev/animations/Animations.java
index 881e183..782075a 100644
--- a/2.1.07-Exercise-Animations/core/src/com/udacity/gamedev/animations/Animations.java
+++ b/2.1.07-Exercise-Animations/core/src/com/udacity/gamedev/animations/Animations.java
@@ -23,14 +23,14 @@ public class Animations extends ApplicationAdapter {
 
     private static final float WALK_LOOP_FRAME_DURATION = 0.1f;
 
-    SpriteBatch batch;
-    ExtendViewport viewport;
+    private SpriteBatch batch;
+    private ExtendViewport viewport;
 
-    Animation walkLoop;
-    long startTime;
+    private Animation walkLoop;
+    private long startTime;
 
-    Animation explosion;
-    DelayedRemovalArray<OneShotAnimation> explosions;
+    private Animation explosion;
+    private DelayedRemovalArray<OneShotAnimation> explosions;
 
     @Override
     public void create() {
@@ -141,12 +141,12 @@ private void updateExplosions() {
     }
 
 
-    class OneShotAnimation {
-        public final Vector2 position;
+    private class OneShotAnimation {
+        final Vector2 position;
         private final Animation animation;
         private final long startTimeNanos;
 
-        public OneShotAnimation(Animation animation, Vector2 position, long startTimeNanos) {
+        OneShotAnimation(Animation animation, Vector2 position, long startTimeNanos) {
             this.animation = animation;
             this.position = position;
             this.startTimeNanos = startTimeNanos;
@@ -156,11 +156,11 @@ private float elapsedTime() {
             return MathUtils.nanoToSec * (TimeUtils.nanoTime() - startTimeNanos);
         }
 
-        public TextureRegion getFrame() {
+        TextureRegion getFrame() {
             return animation.getKeyFrame(elapsedTime());
         }
 
-        public boolean isAnimationFinished() {
+        boolean isAnimationFinished() {
             return animation.isAnimationFinished(elapsedTime());
         }
 
diff --git a/2.1.08-Exercise-CreatingATextureAtlas/build.gradle b/2.1.08-Exercise-CreatingATextureAtlas/build.gradle
index 91a6319..8dce658 100644
--- a/2.1.08-Exercise-CreatingATextureAtlas/build.gradle
+++ b/2.1.08-Exercise-CreatingATextureAtlas/build.gradle
@@ -13,7 +13,7 @@ buildscript {
     }
     dependencies {
         classpath 'de.richsource.gradle.plugins:gwt-gradle-plugin:0.6'
-        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.android.tools.build:gradle:2.3.3'
         classpath 'org.robovm:robovm-gradle-plugin:1.8.0'
         // TODO: Add buildscript dependency on gdx-tools
         classpath "com.badlogicgames.gdx:gdx-tools:1.7.0"
diff --git a/2.1.08-Exercise-CreatingATextureAtlas/core/src/com/udacity/gamedev/textureatlas/TextureAtlasExercise.java b/2.1.08-Exercise-CreatingATextureAtlas/core/src/com/udacity/gamedev/textureatlas/TextureAtlasExercise.java
index 39230f8..71d290c 100644
--- a/2.1.08-Exercise-CreatingATextureAtlas/core/src/com/udacity/gamedev/textureatlas/TextureAtlasExercise.java
+++ b/2.1.08-Exercise-CreatingATextureAtlas/core/src/com/udacity/gamedev/textureatlas/TextureAtlasExercise.java
@@ -9,7 +9,7 @@
 
 public class TextureAtlasExercise extends ApplicationAdapter implements AssetErrorListener {
 
-    public static final String TAG = TextureAtlasExercise.class.getName();
+    private static final String TAG = TextureAtlasExercise.class.getName();
 
     private static final String ATLAS = "images/gigagal.pack.atlas";
     private static final String STANDING_RIGHT = "standing-right";
@@ -17,7 +17,7 @@ public class TextureAtlasExercise extends ApplicationAdapter implements AssetErr
     // TODO: Add an AssetManager
 
 
-    SpriteBatch batch;
+    private SpriteBatch batch;
 
     // TODO: Add an AtlasRegion to hold the standing right sprite