diff --git a/demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java b/demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java
index 15433af92d..e79e557827 100644
--- a/demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java
+++ b/demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java
@@ -21,6 +21,7 @@ import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Handler;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
 import android.view.KeyEvent;
 import android.view.View;
@@ -184,8 +185,8 @@ public class PlayerActivity extends Activity implements OnClickListener, ExoPlay
   }
 
   @Override
-  public void onRequestPermissionsResult(int requestCode, String[] permissions,
-      int[] grantResults) {
+  public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
+      @NonNull int[] grantResults) {
     if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
       initializePlayer();
     } else {
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/drm/FrameworkMediaDrm.java b/library/core/src/main/java/com/google/android/exoplayer2/drm/FrameworkMediaDrm.java
index 1339b90852..e6887af6da 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/drm/FrameworkMediaDrm.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/drm/FrameworkMediaDrm.java
@@ -23,6 +23,7 @@ import android.media.MediaDrm;
 import android.media.NotProvisionedException;
 import android.media.ResourceBusyException;
 import android.media.UnsupportedSchemeException;
+import android.support.annotation.NonNull;
 import com.google.android.exoplayer2.util.Assertions;
 import java.util.HashMap;
 import java.util.Map;
@@ -62,7 +63,8 @@ public final class FrameworkMediaDrm implements ExoMediaDrm<FrameworkMediaCrypto
       final ExoMediaDrm.OnEventListener<? super FrameworkMediaCrypto> listener) {
     mediaDrm.setOnEventListener(listener == null ? null : new MediaDrm.OnEventListener() {
       @Override
-      public void onEvent(MediaDrm md, byte[] sessionId, int event, int extra, byte[] data) {
+      public void onEvent(@NonNull MediaDrm md, byte[] sessionId, int event, int extra,
+          byte[] data) {
         listener.onEvent(FrameworkMediaDrm.this, sessionId, event, extra, data);
       }
     });
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleInputBuffer.java b/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleInputBuffer.java
index 8bb9e790eb..28e67e8623 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleInputBuffer.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/SubtitleInputBuffer.java
@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.text;
 
+import android.support.annotation.NonNull;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 
@@ -35,7 +36,7 @@ public final class SubtitleInputBuffer extends DecoderInputBuffer
   }
 
   @Override
-  public int compareTo(SubtitleInputBuffer other) {
+  public int compareTo(@NonNull SubtitleInputBuffer other) {
     long delta = timeUs - other.timeUs;
     if (delta == 0) {
       return 0;
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Cue.java b/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Cue.java
index e63d1d4118..0a3f36fa87 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Cue.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/cea/Cea708Cue.java
@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.text.cea;
 
+import android.support.annotation.NonNull;
 import android.text.Layout.Alignment;
 import com.google.android.exoplayer2.text.Cue;
 
@@ -55,7 +56,7 @@ import com.google.android.exoplayer2.text.Cue;
   }
 
   @Override
-  public int compareTo(Cea708Cue other) {
+  public int compareTo(@NonNull Cea708Cue other) {
     if (other.priority < priority) {
       return -1;
     } else if (other.priority > priority) {
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCueParser.java b/library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCueParser.java
index 932d4a6bed..30c9c8737e 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCueParser.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/text/webvtt/WebvttCueParser.java
@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.text.webvtt;
 
 import android.graphics.Typeface;
+import android.support.annotation.NonNull;
 import android.text.Layout.Alignment;
 import android.text.Spannable;
 import android.text.SpannableStringBuilder;
@@ -476,7 +477,7 @@ import java.util.regex.Pattern;
     }
 
     @Override
-    public int compareTo(StyleMatch another) {
+    public int compareTo(@NonNull StyleMatch another) {
       return this.score - another.score;
     }
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSourceInputStream.java b/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSourceInputStream.java
index c4296bd6f6..2f2075f354 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSourceInputStream.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/upstream/DataSourceInputStream.java
@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.upstream;
 
+import android.support.annotation.NonNull;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
@@ -71,12 +72,12 @@ public final class DataSourceInputStream extends InputStream {
   }
 
   @Override
-  public int read(byte[] buffer) throws IOException {
+  public int read(@NonNull byte[] buffer) throws IOException {
     return read(buffer, 0, buffer.length);
   }
 
   @Override
-  public int read(byte[] buffer, int offset, int length) throws IOException {
+  public int read(@NonNull byte[] buffer, int offset, int length) throws IOException {
     Assertions.checkState(!closed);
     checkOpened();
     int bytesRead = dataSource.read(buffer, offset, length);
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheSpan.java b/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheSpan.java
index fb96c0fb0e..97d55c5fe2 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheSpan.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheSpan.java
@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.upstream.cache;
 
+import android.support.annotation.NonNull;
 import com.google.android.exoplayer2.C;
 import java.io.File;
 
@@ -95,7 +96,7 @@ public class CacheSpan implements Comparable<CacheSpan> {
   }
 
   @Override
-  public int compareTo(CacheSpan another) {
+  public int compareTo(@NonNull CacheSpan another) {
     if (!key.equals(another.key)) {
       return key.compareTo(another.key);
     }
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedRegionTracker.java b/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedRegionTracker.java
index 0f08ca40f2..9559054f6d 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedRegionTracker.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CachedRegionTracker.java
@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.upstream.cache;
 
+import android.support.annotation.NonNull;
 import android.util.Log;
 import com.google.android.exoplayer2.extractor.ChunkIndex;
 import java.util.Arrays;
@@ -195,7 +196,7 @@ public final class CachedRegionTracker implements Cache.Listener {
     }
 
     @Override
-    public int compareTo(Region another) {
+    public int compareTo(@NonNull Region another) {
       return startOffset < another.startOffset ? -1
           : startOffset == another.startOffset ? 0 : 1;
     }
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/util/AtomicFile.java b/library/core/src/main/java/com/google/android/exoplayer2/util/AtomicFile.java
index c383c01453..f2e30d981b 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/util/AtomicFile.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/util/AtomicFile.java
@@ -16,6 +16,7 @@
 
 package com.google.android.exoplayer2.util;
 
+import android.support.annotation.NonNull;
 import android.util.Log;
 import java.io.File;
 import java.io.FileInputStream;
@@ -185,12 +186,12 @@ public final class AtomicFile {
     }
 
     @Override
-    public void write(byte[] b) throws IOException {
+    public void write(@NonNull byte[] b) throws IOException {
       fileOutputStream.write(b);
     }
 
     @Override
-    public void write(byte[] b, int off, int len) throws IOException {
+    public void write(@NonNull byte[] b, int off, int len) throws IOException {
       fileOutputStream.write(b, off, len);
     }
   }
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/util/Util.java b/library/core/src/main/java/com/google/android/exoplayer2/util/Util.java
index 8fa89dea28..73ea18e2ca 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/util/Util.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/util/Util.java
@@ -25,6 +25,7 @@ import android.content.pm.PackageManager.NameNotFoundException;
 import android.graphics.Point;
 import android.net.Uri;
 import android.os.Build;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
 import android.util.Log;
 import android.view.Display;
@@ -199,7 +200,7 @@ public final class Util {
   public static ExecutorService newSingleThreadExecutor(final String threadName) {
     return Executors.newSingleThreadExecutor(new ThreadFactory() {
       @Override
-      public Thread newThread(Runnable r) {
+      public Thread newThread(@NonNull Runnable r) {
         return new Thread(r, threadName);
       }
     });
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java b/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java
index 059628e0c8..9c7f436bdc 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java
@@ -25,6 +25,7 @@ import android.media.MediaCrypto;
 import android.media.MediaFormat;
 import android.os.Handler;
 import android.os.SystemClock;
+import android.support.annotation.NonNull;
 import android.util.Log;
 import android.view.Surface;
 import com.google.android.exoplayer2.C;
@@ -823,7 +824,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
     }
 
     @Override
-    public void onFrameRendered(MediaCodec codec, long presentationTimeUs, long nanoTime) {
+    public void onFrameRendered(@NonNull MediaCodec codec, long presentationTimeUs, long nanoTime) {
       if (this != tunnelingOnFrameRenderedListener) {
         // Stale event.
         return;
diff --git a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/RepresentationKey.java b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/RepresentationKey.java
index 51451a83c2..cf17a081d7 100644
--- a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/RepresentationKey.java
+++ b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/RepresentationKey.java
@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.source.dash.manifest;
 
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.NonNull;
 
 /**
  * Uniquely identifies a {@link Representation} in a {@link DashManifest}.
@@ -68,7 +69,7 @@ public final class RepresentationKey implements Parcelable, Comparable<Represent
   // Comparable implementation.
 
   @Override
-  public int compareTo(RepresentationKey o) {
+  public int compareTo(@NonNull RepresentationKey o) {
     int result = periodIndex - o.periodIndex;
     if (result == 0) {
       result = adaptationSetIndex - o.adaptationSetIndex;
diff --git a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java
index 9ef28bdb8d..6b6e15e915 100644
--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java
@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.source.hls.playlist;
 
 import android.support.annotation.IntDef;
+import android.support.annotation.NonNull;
 import com.google.android.exoplayer2.C;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -61,7 +62,7 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
     }
 
     @Override
-    public int compareTo(Long relativeStartTimeUs) {
+    public int compareTo(@NonNull Long relativeStartTimeUs) {
       return this.relativeStartTimeUs > relativeStartTimeUs
           ? 1 : (this.relativeStartTimeUs < relativeStartTimeUs ? -1 : 0);
     }