Make classes/methods final to prevent uncontrolled extension.

library/src/androidTest/java/com/google/android/exoplayer/TimeRangeTest.java

@@ -25,10 +25,10 @@ public class TimeRangeTest extends TestCase {
   public void testEquals() {
     TimeRange timeRange1 = new TimeRange(TimeRange.TYPE_SNAPSHOT, 0, 30000000);
     assertTrue(timeRange1.equals(timeRange1));
-    
+
     TimeRange timeRange2 = new TimeRange(TimeRange.TYPE_SNAPSHOT, 0, 30000000);
     assertTrue(timeRange1.equals(timeRange2));
-    
+
     TimeRange timeRange3 = new TimeRange(TimeRange.TYPE_SNAPSHOT, 0, 60000000);
     assertFalse(timeRange1.equals(timeRange3));
   }

library/src/androidTest/java/com/google/android/exoplayer/dash/DashChunkSourceTest.java

@@ -82,7 +82,6 @@ public class DashChunkSourceTest extends InstrumentationTestCase {
       new Format("3", "video/mp4", WIDE_WIDTH, 50, -1, -1, -1, 1000);
 
   @Mock private DataSource mockDataSource;
-  @Mock private ManifestFetcher<MediaPresentationDescription> mockManifestFetcher;
 
   @Override
   public void setUp() throws Exception {

library/src/main/java/com/google/android/exoplayer/BehindLiveWindowException.java

@@ -20,7 +20,7 @@ import java.io.IOException;
 /**
  * Thrown when a live playback falls behind the available media window.
  */
-public class BehindLiveWindowException extends IOException {
+public final class BehindLiveWindowException extends IOException {
 
   public BehindLiveWindowException() {
     super();

library/src/main/java/com/google/android/exoplayer/CryptoInfo.java

@@ -23,7 +23,7 @@ import android.media.MediaExtractor;
 /**
  * Compatibility wrapper around {@link android.media.MediaCodec.CryptoInfo}.
  */
-public class CryptoInfo {
+public final class CryptoInfo {
 
   /**
    * @see android.media.MediaCodec.CryptoInfo#iv

library/src/main/java/com/google/android/exoplayer/DefaultLoadControl.java

@@ -39,7 +39,7 @@ import java.util.List;
  * itself as a task with priority {@link NetworkLock#STREAMING_PRIORITY} during loading periods,
  * and unregistering itself during draining periods.
  */
-public class DefaultLoadControl implements LoadControl {
+public final class DefaultLoadControl implements LoadControl {
 
   /**
    * Interface definition for a callback to be notified of {@link DefaultLoadControl} events.

library/src/main/java/com/google/android/exoplayer/DummyTrackRenderer.java

@@ -22,7 +22,7 @@ package com.google.android.exoplayer;
  * to request that it should be ignored. {@link IllegalStateException} is thrown from all methods
  * that are documented to indicate that they should not be invoked unless the renderer is prepared.
  */
-public class DummyTrackRenderer extends TrackRenderer {
+public final class DummyTrackRenderer extends TrackRenderer {
 
   @Override
   protected int doPrepare(long positionUs) {

library/src/main/java/com/google/android/exoplayer/ExoPlayerLibraryInfo.java

@@ -18,10 +18,7 @@ package com.google.android.exoplayer;
 /**
  * Information about the ExoPlayer library.
  */
-// TODO: This file should be automatically generated by the build system.
-public class ExoPlayerLibraryInfo {
-
-  private ExoPlayerLibraryInfo() {}
+public final class ExoPlayerLibraryInfo {
 
   /**
    * The version of the library, expressed as a string.
@@ -48,4 +45,6 @@ public class ExoPlayerLibraryInfo {
    */
   public static final boolean TRACE_ENABLED = true;
 
+  private ExoPlayerLibraryInfo() {}
+
 }

library/src/main/java/com/google/android/exoplayer/MediaCodecUtil.java

@@ -34,7 +34,7 @@ import java.util.HashMap;
  * A utility class for querying the available codecs.
  */
 @TargetApi(16)
-public class MediaCodecUtil {
+public final class MediaCodecUtil {
 
   /**
    * Thrown when an error occurs querying the device for its underlying media capabilities.
@@ -54,6 +54,8 @@ public class MediaCodecUtil {
 
   private static final HashMap<CodecKey, Pair<String, CodecCapabilities>> codecs = new HashMap<>();
 
+  private MediaCodecUtil() {}
+
   /**
    * Get information about the decoder that will be used for a given mime type.
    *

library/src/main/java/com/google/android/exoplayer/MediaFormat.java

@@ -29,7 +29,7 @@ import java.util.List;
 /**
  * Defines the format of an elementary media stream.
  */
-public class MediaFormat {
+public final class MediaFormat {
 
   private static final String KEY_PIXEL_WIDTH_HEIGHT_RATIO =
       "com.google.android.videos.pixelWidthHeightRatio";

library/src/main/java/com/google/android/exoplayer/SmoothFrameReleaseTimeHelper.java

@@ -25,7 +25,7 @@ import android.view.Choreographer.FrameCallback;
  * Makes a best effort to adjust frame release timestamps for a smoother visual result.
  */
 @TargetApi(16)
-public class SmoothFrameReleaseTimeHelper implements FrameReleaseTimeHelper, FrameCallback {
+public final class SmoothFrameReleaseTimeHelper implements FrameReleaseTimeHelper, FrameCallback {
 
   private static final long CHOREOGRAPHER_SAMPLE_DELAY_MILLIS = 500;
   private static final long MAX_ALLOWED_DRIFT_NS = 20000000;

library/src/main/java/com/google/android/exoplayer/StandaloneMediaClock.java

@@ -21,7 +21,7 @@ import android.os.SystemClock;
  * A standalone {@link MediaClock}. The clock can be started, stopped and its time can be set and
  * retrieved. When started, this clock is based on {@link SystemClock#elapsedRealtime()}.
  */
-/* package */ class StandaloneMediaClock implements MediaClock {
+/* package */ final class StandaloneMediaClock implements MediaClock {
 
   private boolean started;
 

library/src/main/java/com/google/android/exoplayer/chunk/ContainerMediaChunk.java

@@ -74,68 +74,69 @@ public class ContainerMediaChunk extends BaseMediaChunk implements SingleTrackOu
   }
 
   @Override
-  public long bytesLoaded() {
+  public final long bytesLoaded() {
     return bytesLoaded;
   }
 
   @Override
-  public MediaFormat getMediaFormat() {
+  public final MediaFormat getMediaFormat() {
     return mediaFormat;
   }
 
   @Override
-  public DrmInitData getDrmInitData() {
+  public final DrmInitData getDrmInitData() {
     return drmInitData;
   }
 
   // SingleTrackOutput implementation.
 
   @Override
-  public void seekMap(SeekMap seekMap) {
+  public final void seekMap(SeekMap seekMap) {
     // Do nothing.
   }
 
   @Override
-  public void drmInitData(DrmInitData drmInitData) {
+  public final void drmInitData(DrmInitData drmInitData) {
     this.drmInitData = drmInitData;
   }
 
   @Override
-  public void format(MediaFormat mediaFormat) {
+  public final void format(MediaFormat mediaFormat) {
     this.mediaFormat = mediaFormat;
   }
 
   @Override
-  public int sampleData(ExtractorInput input, int length, boolean allowEndOfInput)
+  public final int sampleData(ExtractorInput input, int length, boolean allowEndOfInput)
       throws IOException, InterruptedException {
     return getOutput().sampleData(input, length, allowEndOfInput);
   }
 
   @Override
-  public void sampleData(ParsableByteArray data, int length) {
+  public final void sampleData(ParsableByteArray data, int length) {
     getOutput().sampleData(data, length);
   }
 
   @Override
-  public void sampleMetadata(long timeUs, int flags, int size, int offset, byte[] encryptionKey) {
+  public final void sampleMetadata(long timeUs, int flags, int size, int offset,
+      byte[] encryptionKey) {
     getOutput().sampleMetadata(timeUs + sampleOffsetUs, flags, size, offset, encryptionKey);
   }
 
   // Loadable implementation.
 
   @Override
-  public void cancelLoad() {
+  public final void cancelLoad() {
     loadCanceled = true;
   }
 
   @Override
-  public boolean isLoadCanceled() {
+  public final boolean isLoadCanceled() {
     return loadCanceled;
   }
 
   @SuppressWarnings("NonAtomicVolatileUpdate")
   @Override
-  public void load() throws IOException, InterruptedException {
+  public final void load() throws IOException, InterruptedException {
     DataSpec loadDataSpec = Util.getRemainderDataSpec(dataSpec, bytesLoaded);
     try {
       // Create and open the input.

library/src/main/java/com/google/android/exoplayer/chunk/MultiTrackChunkSource.java

@@ -28,7 +28,7 @@ import java.util.List;
  * A {@link ChunkSource} providing the ability to switch between multiple other {@link ChunkSource}
  * instances.
  */
-public class MultiTrackChunkSource implements ChunkSource, ExoPlayerComponent {
+public final class MultiTrackChunkSource implements ChunkSource, ExoPlayerComponent {
 
   /**
    * A message to indicate a source selection. Source selection can only be performed when the

library/src/main/java/com/google/android/exoplayer/chunk/SingleSampleChunkSource.java

@@ -29,7 +29,7 @@ import java.util.List;
  * An example use case for this implementation is to act as the source for loading out-of-band
  * subtitles, where subtitles for the entire video are delivered as a single file.
  */
-public class SingleSampleChunkSource implements ChunkSource {
+public final class SingleSampleChunkSource implements ChunkSource {
 
   private final DataSource dataSource;
   private final DataSpec dataSpec;

library/src/main/java/com/google/android/exoplayer/dash/DashWrappingSegmentIndex.java

@@ -22,7 +22,7 @@ import com.google.android.exoplayer.extractor.ChunkIndex;
  * An implementation of {@link DashSegmentIndex} that wraps a {@link ChunkIndex} parsed from a
  * media stream.
  */
-public class DashWrappingSegmentIndex implements DashSegmentIndex {
+/* package */ final class DashWrappingSegmentIndex implements DashSegmentIndex {
 
   private final ChunkIndex chunkIndex;
   private final String uri;

library/src/main/java/com/google/android/exoplayer/dash/mpd/DashSingleSegmentIndex.java

@@ -13,14 +13,14 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.google.android.exoplayer.dash;
+package com.google.android.exoplayer.dash.mpd;
 
-import com.google.android.exoplayer.dash.mpd.RangedUri;
+import com.google.android.exoplayer.dash.DashSegmentIndex;
 
 /**
  * A {@link DashSegmentIndex} that defines a single segment.
  */
-public class DashSingleSegmentIndex implements DashSegmentIndex {
+/* package */ final class DashSingleSegmentIndex implements DashSegmentIndex {
 
   private final long startTimeUs;
   private final long durationUs;

library/src/main/java/com/google/android/exoplayer/dash/mpd/Representation.java

@@ -18,7 +18,6 @@ package com.google.android.exoplayer.dash.mpd;
 import com.google.android.exoplayer.chunk.Format;
 import com.google.android.exoplayer.chunk.FormatWrapper;
 import com.google.android.exoplayer.dash.DashSegmentIndex;
-import com.google.android.exoplayer.dash.DashSingleSegmentIndex;
 import com.google.android.exoplayer.dash.mpd.SegmentBase.MultiSegmentBase;
 import com.google.android.exoplayer.dash.mpd.SegmentBase.SingleSegmentBase;
 

library/src/main/java/com/google/android/exoplayer/dash/mpd/UtcTimingElement.java

@@ -18,7 +18,7 @@ package com.google.android.exoplayer.dash.mpd;
 /**
  * Represents a UTCTiming element.
  */
-public class UtcTimingElement {
+public final class UtcTimingElement {
 
   public final String schemeIdUri;
   public final String value;

library/src/main/java/com/google/android/exoplayer/dash/mpd/UtcTimingElementResolver.java

@@ -38,7 +38,7 @@ import java.util.concurrent.CancellationException;
 /**
  * Resolves a {@link UtcTimingElement}.
  */
-public class UtcTimingElementResolver implements Loader.Callback {
+public final class UtcTimingElementResolver implements Loader.Callback {
 
   /**
    * Callback for timing element resolution.

library/src/main/java/com/google/android/exoplayer/extractor/ExtractorSampleSource.java

@@ -67,8 +67,8 @@ import java.util.List;
  * constructor. When reading a new stream, the first {@link Extractor} that returns {@code true}
  * from {@link Extractor#sniff(ExtractorInput)} will be used.
  */
-public class ExtractorSampleSource implements SampleSource, SampleSourceReader, ExtractorOutput,
-    Loader.Callback {
+public final class ExtractorSampleSource implements SampleSource, SampleSourceReader,
+    ExtractorOutput, Loader.Callback {
 
   /**
    * Thrown if the input format could not recognized.

library/src/main/java/com/google/android/exoplayer/extractor/ts/AdtsExtractor.java

@@ -29,7 +29,7 @@ import java.io.IOException;
  * Facilitates the extraction of AAC samples from elementary audio files formatted as AAC with ADTS
  * headers.
  */
-public class AdtsExtractor implements Extractor {
+public final class AdtsExtractor implements Extractor {
 
   private static final int MAX_PACKET_SIZE = 200;
 

library/src/main/java/com/google/android/exoplayer/extractor/ts/AdtsReader.java

@@ -30,7 +30,7 @@ import java.util.Collections;
 /**
  * Parses a continuous ADTS byte stream and extracts individual frames.
  */
-/* package */ class AdtsReader extends ElementaryStreamReader {
+/* package */ final class AdtsReader extends ElementaryStreamReader {
 
   private static final int STATE_FINDING_SYNC = 0;
   private static final int STATE_READING_HEADER = 1;

library/src/main/java/com/google/android/exoplayer/extractor/ts/H264Reader.java

@@ -32,7 +32,7 @@ import java.util.List;
 /**
  * Parses a continuous H264 byte stream and extracts individual frames.
  */
-/* package */ class H264Reader extends ElementaryStreamReader {
+/* package */ final class H264Reader extends ElementaryStreamReader {
 
   private static final String TAG = "H264Reader";
 

library/src/main/java/com/google/android/exoplayer/extractor/ts/H265Reader.java

@@ -30,7 +30,7 @@ import java.util.Collections;
 /**
  * Parses a continuous H.265 byte stream and extracts individual frames.
  */
-/* package */ class H265Reader extends ElementaryStreamReader {
+/* package */ final class H265Reader extends ElementaryStreamReader {
 
   private static final String TAG = "H265Reader";
 

library/src/main/java/com/google/android/exoplayer/extractor/ts/Id3Reader.java

@@ -24,7 +24,7 @@ import com.google.android.exoplayer.util.ParsableByteArray;
 /**
  * Parses ID3 data and extracts individual text information frames.
  */
-/* package */ class Id3Reader extends ElementaryStreamReader {
+/* package */ final class Id3Reader extends ElementaryStreamReader {
 
   // State that should be reset on seek.
   private boolean writingSample;

library/src/main/java/com/google/android/exoplayer/extractor/ts/MpegAudioReader.java

@@ -24,7 +24,7 @@ import com.google.android.exoplayer.util.ParsableByteArray;
 /**
  * Parses a continuous MPEG Audio byte stream and extracts individual frames.
  */
-/* package */ class MpegAudioReader extends ElementaryStreamReader {
+/* package */ final class MpegAudioReader extends ElementaryStreamReader {
 
   private static final int STATE_FINDING_HEADER = 0;
   private static final int STATE_READING_HEADER = 1;

library/src/main/java/com/google/android/exoplayer/extractor/ts/SeiReader.java

@@ -28,7 +28,7 @@ import com.google.android.exoplayer.util.ParsableByteArray;
  * TODO: Technically, we shouldn't allow a sample to be read from the queue until we're sure that
  * a sample with an earlier timestamp won't be added to it.
  */
-/* package */ class SeiReader extends ElementaryStreamReader {
+/* package */ final class SeiReader extends ElementaryStreamReader {
 
   public SeiReader(TrackOutput output) {
     super(output);

library/src/main/java/com/google/android/exoplayer/extractor/webm/VarintReader.java

@@ -8,7 +8,7 @@ import java.io.IOException;
 /**
  * Reads EBML variable-length integers (varints) from an {@link ExtractorInput}.
  */
-/* package */ class VarintReader {
+/* package */ final class VarintReader {
 
   private static final int STATE_BEGIN_READING = 0;
   private static final int STATE_READ_CONTENTS = 1;

library/src/main/java/com/google/android/exoplayer/hls/HlsSampleSource.java

@@ -40,7 +40,7 @@ import java.util.LinkedList;
 /**
  * A {@link SampleSource} for HLS streams.
  */
-public class HlsSampleSource implements SampleSource, SampleSourceReader, Loader.Callback {
+public final class HlsSampleSource implements SampleSource, SampleSourceReader, Loader.Callback {
 
   /**
    * Interface definition for a callback to be notified of {@link HlsSampleSource} events.
@@ -561,7 +561,7 @@ public class HlsSampleSource implements SampleSource, SampleSourceReader, Loader
     return Math.min((errorCount - 1) * 1000, 5000);
   }
 
-  protected final int usToMs(long timeUs) {
+  /* package */ int usToMs(long timeUs) {
     return (int) (timeUs / 1000);
   }
 

library/src/main/java/com/google/android/exoplayer/metadata/GeobMetadata.java

@@ -19,7 +19,7 @@ package com.google.android.exoplayer.metadata;
  * A metadata that contains parsed ID3 GEOB (General Encapsulated Object) frame data associated
  * with time indices.
  */
-public class GeobMetadata {
+public final class GeobMetadata {
 
   public static final String TYPE = "GEOB";
 

library/src/main/java/com/google/android/exoplayer/metadata/Id3Parser.java

@@ -28,7 +28,7 @@ import java.util.Map;
 /**
  * Extracts individual TXXX text frames from raw ID3 data.
  */
-public class Id3Parser implements MetadataParser<Map<String, Object>> {
+public final class Id3Parser implements MetadataParser<Map<String, Object>> {
 
   private static final int ID3_TEXT_ENCODING_ISO_8859_1 = 0;
   private static final int ID3_TEXT_ENCODING_UTF_16 = 1;

library/src/main/java/com/google/android/exoplayer/metadata/MetadataTrackRenderer.java

@@ -35,7 +35,7 @@ import java.io.IOException;
  *
  * @param <T> The type of the metadata.
  */
-public class MetadataTrackRenderer<T> extends TrackRenderer implements Callback {
+public final class MetadataTrackRenderer<T> extends TrackRenderer implements Callback {
 
   /**
    * An interface for components that process metadata.

library/src/main/java/com/google/android/exoplayer/metadata/PrivMetadata.java

@@ -19,7 +19,7 @@ package com.google.android.exoplayer.metadata;
  * A metadata that contains parsed ID3 PRIV (Private) frame data associated
  * with time indices.
  */
-public class PrivMetadata {
+public final class PrivMetadata {
 
   public static final String TYPE = "PRIV";
 

library/src/main/java/com/google/android/exoplayer/metadata/TxxxMetadata.java

@@ -19,7 +19,7 @@ package com.google.android.exoplayer.metadata;
  * A metadata that contains parsed ID3 TXXX (User defined text information) frame data associated
  * with time indices.
  */
-public class TxxxMetadata {
+public final class TxxxMetadata {
 
   public static final String TYPE = "TXXX";
 

library/src/main/java/com/google/android/exoplayer/text/SubtitleParserHelper.java

@@ -31,7 +31,7 @@ import java.io.InputStream;
  * Wraps a {@link SubtitleParser}, exposing an interface similar to {@link MediaCodec} for
  * asynchronous parsing of subtitles.
  */
-public class SubtitleParserHelper implements Handler.Callback {
+public final class SubtitleParserHelper implements Handler.Callback {
 
   private final SubtitleParser parser;
 

library/src/main/java/com/google/android/exoplayer/text/TextTrackRenderer.java

@@ -58,7 +58,7 @@ import java.util.List;
  * {@link SubtitleParser#canParse(String)} will be used.
  */
 @TargetApi(16)
-public class TextTrackRenderer extends TrackRenderer implements Callback {
+public final class TextTrackRenderer extends TrackRenderer implements Callback {
 
   private static final int MSG_UPDATE_OVERLAY = 0;
 

library/src/main/java/com/google/android/exoplayer/text/eia608/Eia608Parser.java

@@ -26,7 +26,7 @@ import java.util.ArrayList;
  * Facilitates the extraction and parsing of EIA-608 (a.k.a. "line 21 captions" and "CEA-608")
  * Closed Captions from the SEI data block from H.264.
  */
-public class Eia608Parser {
+public final class Eia608Parser {
 
   private static final int PAYLOAD_TYPE_CC = 4;
   private static final int COUNTRY_CODE = 0xB5;

library/src/main/java/com/google/android/exoplayer/text/eia608/Eia608TrackRenderer.java

@@ -39,7 +39,7 @@ import java.util.TreeSet;
 /**
  * A {@link TrackRenderer} for EIA-608 closed captions in a media stream.
  */
-public class Eia608TrackRenderer extends TrackRenderer implements Callback {
+public final class Eia608TrackRenderer extends TrackRenderer implements Callback {
 
   private static final int MSG_INVOKE_RENDERER = 0;
 

library/src/main/java/com/google/android/exoplayer/text/ttml/TtmlParser.java

@@ -54,7 +54,7 @@ import java.util.regex.Pattern;
  * </p>
  * @see <a href="http://www.w3.org/TR/ttaf1-dfxp/">TTML specification</a>
  */
-public class TtmlParser implements SubtitleParser {
+public final class TtmlParser implements SubtitleParser {
 
   private static final String TAG = "TtmlParser";
 

library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttParser.java

@@ -91,7 +91,7 @@ public class WebvttParser implements SubtitleParser {
   }
 
   @Override
-  public WebvttSubtitle parse(InputStream inputStream, String inputEncoding, long startTimeUs)
+  public final WebvttSubtitle parse(InputStream inputStream, String inputEncoding, long startTimeUs)
       throws IOException {
     ArrayList<WebvttCue> subtitles = new ArrayList<>();
     long mediaTimestampUs = startTimeUs;
@@ -253,7 +253,7 @@ public class WebvttParser implements SubtitleParser {
   }
 
   @Override
-  public boolean canParse(String mimeType) {
+  public final boolean canParse(String mimeType) {
     return MimeTypes.TEXT_VTT.equals(mimeType);
   }
 

library/src/main/java/com/google/android/exoplayer/text/webvtt/WebvttSubtitle.java

@@ -30,7 +30,7 @@ import java.util.List;
 /**
  * A representation of a WebVTT subtitle.
  */
-public class WebvttSubtitle implements Subtitle {
+public final class WebvttSubtitle implements Subtitle {
 
   private final List<WebvttCue> cues;
   private final int numCues;

library/src/main/java/com/google/android/exoplayer/upstream/ByteArrayDataSink.java

@@ -24,7 +24,7 @@ import java.io.IOException;
 /**
  * A {@link DataSink} for writing to a byte array.
  */
-public class ByteArrayDataSink implements DataSink {
+public final class ByteArrayDataSink implements DataSink {
 
   private ByteArrayOutputStream stream;
 

library/src/main/java/com/google/android/exoplayer/upstream/ByteArrayDataSource.java

@@ -23,7 +23,7 @@ import java.io.IOException;
 /**
  * A {@link DataSource} for reading from a byte array.
  */
-public class ByteArrayDataSource implements DataSource {
+public final class ByteArrayDataSource implements DataSource {
 
   private final byte[] data;
   private int readPosition;

library/src/main/java/com/google/android/exoplayer/upstream/DataSourceInputStream.java

@@ -24,7 +24,7 @@ import java.io.InputStream;
  * Allows data corresponding to a given {@link DataSpec} to be read from a {@link DataSource} and
  * consumed as an {@link InputStream}.
  */
-public class DataSourceInputStream extends InputStream {
+public final class DataSourceInputStream extends InputStream {
 
   private final DataSource dataSource;
   private final DataSpec dataSpec;

library/src/main/java/com/google/android/exoplayer/upstream/DefaultBandwidthMeter.java

@@ -26,7 +26,7 @@ import android.os.Handler;
  * Counts transferred bytes while transfers are open and creates a bandwidth sample and updated
  * bandwidth estimate each time a transfer ends.
  */
-public class DefaultBandwidthMeter implements BandwidthMeter {
+public final class DefaultBandwidthMeter implements BandwidthMeter {
 
   public static final int DEFAULT_MAX_WEIGHT = 2000;
 

library/src/main/java/com/google/android/exoplayer/upstream/PriorityDataSource.java

@@ -24,7 +24,7 @@ import java.io.IOException;
  * priority is the highest priority of any task. {@link NetworkLock.PriorityTooLowException} is
  * thrown when this condition does not hold.
  */
-public class PriorityDataSource implements DataSource {
+public final class PriorityDataSource implements DataSource {
 
   private final DataSource upstream;
   private final int priority;

library/src/main/java/com/google/android/exoplayer/upstream/UdpDataSource.java

@@ -27,7 +27,7 @@ import java.net.MulticastSocket;
 /**
  * A UDP {@link DataSource}.
  */
-public class UdpDataSource implements UriDataSource {
+public final class UdpDataSource implements UriDataSource {
 
   /**
    * Thrown when an error is encountered when trying to read from a {@link UdpDataSource}.

library/src/main/java/com/google/android/exoplayer/upstream/cache/CacheDataSink.java

@@ -29,7 +29,7 @@ import java.io.IOException;
 /**
  * Writes data into a cache.
  */
-public class CacheDataSink implements DataSink {
+public final class CacheDataSink implements DataSink {
 
   private final Cache cache;
   private final long maxCacheFileSize;

library/src/main/java/com/google/android/exoplayer/upstream/cache/LeastRecentlyUsedCacheEvictor.java

@@ -21,7 +21,7 @@ import java.util.TreeSet;
 /**
  * Evicts least recently used cache files first.
  */
-public class LeastRecentlyUsedCacheEvictor implements CacheEvictor, Comparator<CacheSpan> {
+public final class LeastRecentlyUsedCacheEvictor implements CacheEvictor, Comparator<CacheSpan> {
 
   private final long maxBytes;
   private final TreeSet<CacheSpan> leastRecentlyUsed;

library/src/main/java/com/google/android/exoplayer/upstream/cache/NoOpCacheEvictor.java

@@ -22,7 +22,7 @@ package com.google.android.exoplayer.upstream.cache;
  * Warning: Using this evictor might have unforeseeable consequences if cache
  * size is not managed elsewhere.
  */
-public class NoOpCacheEvictor implements CacheEvictor {
+public final class NoOpCacheEvictor implements CacheEvictor {
 
   @Override
   public void onStartFile(Cache cache, String key, long position, long length) {

library/src/main/java/com/google/android/exoplayer/upstream/cache/SimpleCache.java

@@ -32,7 +32,7 @@ import java.util.TreeSet;
 /**
  * A {@link Cache} implementation that maintains an in-memory representation.
  */
-public class SimpleCache implements Cache {
+public final class SimpleCache implements Cache {
 
   private final File cacheDir;
   private final CacheEvictor evictor;

library/src/main/java/com/google/android/exoplayer/util/MimeTypes.java

@@ -23,7 +23,7 @@ import android.media.AudioFormat;
 /**
  * Defines common MIME types and helper methods.
  */
-public class MimeTypes {
+public final class MimeTypes {
 
   public static final String BASE_TYPE_VIDEO = "video";
   public static final String BASE_TYPE_AUDIO = "audio";

library/src/main/java/com/google/android/exoplayer/util/PriorityHandlerThread.java

@@ -21,7 +21,7 @@ import android.os.Process;
 /**
  * A {@link HandlerThread} with a specified process priority.
  */
-public class PriorityHandlerThread extends HandlerThread {
+public final class PriorityHandlerThread extends HandlerThread {
 
   private final int priority;
 

library/src/main/java/com/google/android/exoplayer/util/SlidingPercentile.java

@@ -31,7 +31,7 @@ import java.util.Comparator;
  * @see <a href="http://en.wikipedia.org/wiki/Moving_average">Wiki: Moving average</a>
  * @see <a href="http://en.wikipedia.org/wiki/Selection_algorithm">Wiki: Selection algorithm</a>
  */
-public class SlidingPercentile {
+public final class SlidingPercentile {
 
   // Orderings.
   private static final Comparator<Sample> INDEX_COMPARATOR = new Comparator<Sample>() {

library/src/main/java/com/google/android/exoplayer/util/TraceUtil.java

@@ -22,7 +22,9 @@ import android.annotation.TargetApi;
 /**
  * Calls through to {@link android.os.Trace} methods on supported API levels.
  */
-public class TraceUtil {
+public final class TraceUtil {
+
+  private TraceUtil() {}
 
   /**
    * Writes a trace message to indicate that a given section of code has begun.

library/src/main/java/com/google/android/exoplayer/util/VerboseLogUtil.java

@@ -18,14 +18,12 @@ package com.google.android.exoplayer.util;
 /**
  * Utility class for managing a set of tags for which verbose logging should be enabled.
  */
-public class VerboseLogUtil {
+public final class VerboseLogUtil {
 
   private static volatile String[] enabledTags;
   private static volatile boolean enableAllTags;
 
-  private VerboseLogUtil() {
-    // Private constructor to prevent instantiation.
-  }
+  private VerboseLogUtil() {}
 
   /**
    * Sets the tags for which verbose logging should be enabled.