diff --git a/instrumentation/src/androidTest/java/com/bumptech/glide/test/WaitModelLoader.java b/instrumentation/src/androidTest/java/com/bumptech/glide/test/WaitModelLoader.java
index 358a542637..2c89c9227c 100644
--- a/instrumentation/src/androidTest/java/com/bumptech/glide/test/WaitModelLoader.java
+++ b/instrumentation/src/androidTest/java/com/bumptech/glide/test/WaitModelLoader.java
@@ -83,6 +83,7 @@ public static synchronized <T> WaitModel<T> waitOn(T model) {
       return new WaitModel<>(model);
     }
 
+    @NonNull
     @Override
     public ModelLoader<WaitModel<Model>, Data> build(
         MultiModelLoaderFactory multiFactory) {
@@ -106,7 +107,7 @@ private static final class WaitFetcher<Data> implements DataFetcher<Data> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super Data> callback) {
+    public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super Data> callback) {
       ConcurrencyHelper.waitOnLatch(toWaitOn);
       wrapped.loadData(priority, callback);
     }
diff --git a/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpStreamFetcher.java b/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpStreamFetcher.java
index 2bbc438a97..dcac2f7688 100644
--- a/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpStreamFetcher.java
+++ b/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpStreamFetcher.java
@@ -38,7 +38,8 @@ public OkHttpStreamFetcher(OkHttpClient client, GlideUrl url) {
   }
 
   @Override
-  public void loadData(Priority priority, final DataCallback<? super InputStream> callback) {
+  public void loadData(@NonNull Priority priority,
+      @NonNull final DataCallback<? super InputStream> callback) {
     Request.Builder requestBuilder = new Request.Builder().url(url.toStringUrl());
     for (Map.Entry<String, String> headerEntry : url.getHeaders().entrySet()) {
       String key = headerEntry.getKey();
diff --git a/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpUrlLoader.java b/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpUrlLoader.java
index c5374ba686..174c446f2a 100644
--- a/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpUrlLoader.java
+++ b/integration/okhttp/src/main/java/com/bumptech/glide/integration/okhttp/OkHttpUrlLoader.java
@@ -1,5 +1,6 @@
 package com.bumptech.glide.integration.okhttp;
 
+import android.support.annotation.NonNull;
 import com.bumptech.glide.load.Options;
 import com.bumptech.glide.load.model.GlideUrl;
 import com.bumptech.glide.load.model.ModelLoader;
@@ -25,14 +26,14 @@ public OkHttpUrlLoader(OkHttpClient client) {
   }
 
   @Override
-  public boolean handles(GlideUrl url) {
+  public boolean handles(@NonNull GlideUrl url) {
     return true;
   }
 
   @SuppressWarnings("deprecation")
   @Override
-  public LoadData<InputStream> buildLoadData(GlideUrl model, int width, int height,
-      Options options) {
+  public LoadData<InputStream> buildLoadData(@NonNull GlideUrl model, int width, int height,
+      @NonNull Options options) {
     return new LoadData<>(model, new OkHttpStreamFetcher(client, model));
   }
 
@@ -70,6 +71,7 @@ public Factory(OkHttpClient client) {
       this.client = client;
     }
 
+    @NonNull
     @SuppressWarnings("deprecation")
     @Override
     public ModelLoader<GlideUrl, InputStream> build(MultiModelLoaderFactory multiFactory) {
diff --git a/integration/okhttp3/src/main/java/com/bumptech/glide/integration/okhttp3/OkHttpStreamFetcher.java b/integration/okhttp3/src/main/java/com/bumptech/glide/integration/okhttp3/OkHttpStreamFetcher.java
index 7ffd81db6c..7855929053 100644
--- a/integration/okhttp3/src/main/java/com/bumptech/glide/integration/okhttp3/OkHttpStreamFetcher.java
+++ b/integration/okhttp3/src/main/java/com/bumptech/glide/integration/okhttp3/OkHttpStreamFetcher.java
@@ -22,8 +22,7 @@
 /**
  * Fetches an {@link InputStream} using the okhttp library.
  */
-public class OkHttpStreamFetcher implements DataFetcher<InputStream>,
- okhttp3.Callback {
+public class OkHttpStreamFetcher implements DataFetcher<InputStream>, okhttp3.Callback {
   private static final String TAG = "OkHttpFetcher";
   private final Call.Factory client;
   private final GlideUrl url;
@@ -40,7 +39,8 @@ public OkHttpStreamFetcher(Call.Factory client, GlideUrl url) {
   }
 
   @Override
-  public void loadData(Priority priority, final DataCallback<? super InputStream> callback) {
+  public void loadData(@NonNull Priority priority,
+      @NonNull final DataCallback<? super InputStream> callback) {
     Request.Builder requestBuilder = new Request.Builder().url(url.toStringUrl());
     for (Map.Entry<String, String> headerEntry : url.getHeaders().entrySet()) {
       String key = headerEntry.getKey();
diff --git a/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyStreamFetcher.java b/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyStreamFetcher.java
index f43ff78252..97348ecc6e 100644
--- a/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyStreamFetcher.java
+++ b/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyStreamFetcher.java
@@ -2,7 +2,6 @@
 
 import android.support.annotation.NonNull;
 import android.util.Log;
-import com.android.volley.AuthFailureError;
 import com.android.volley.NetworkResponse;
 import com.android.volley.Request;
 import com.android.volley.RequestQueue;
@@ -51,7 +50,8 @@ public VolleyStreamFetcher(RequestQueue requestQueue, GlideUrl url,
   }
 
   @Override
-  public void loadData(Priority priority, DataCallback<? super InputStream> callback) {
+  public void loadData(@NonNull Priority priority,
+      @NonNull DataCallback<? super InputStream> callback) {
     request = requestFactory.create(url.toStringUrl(), callback, glideToVolleyPriority(priority),
         url.getHeaders());
     requestQueue.add(request);
@@ -82,7 +82,7 @@ public DataSource getDataSource() {
     return DataSource.REMOTE;
   }
 
-  private static Request.Priority glideToVolleyPriority(Priority priority) {
+  private static Request.Priority glideToVolleyPriority(@NonNull Priority priority) {
     switch (priority) {
       case LOW:
         return Request.Priority.LOW;
@@ -119,7 +119,7 @@ public GlideRequest(String url, DataCallback<? super InputStream> callback, Prio
     }
 
     @Override
-    public Map<String, String> getHeaders() throws AuthFailureError {
+    public Map<String, String> getHeaders() {
       return headers;
     }
 
diff --git a/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyUrlLoader.java b/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyUrlLoader.java
index d64a47d409..a5ceda30a9 100644
--- a/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyUrlLoader.java
+++ b/integration/volley/src/main/java/com/bumptech/glide/integration/volley/VolleyUrlLoader.java
@@ -77,6 +77,7 @@ public Factory(RequestQueue requestQueue, VolleyRequestFactory requestFactory) {
       this.requestQueue = requestQueue;
     }
 
+    @NonNull
     @Override
     public ModelLoader<GlideUrl, InputStream> build(MultiModelLoaderFactory factory) {
       return new VolleyUrlLoader(requestQueue, requestFactory);
diff --git a/library/src/main/java/com/bumptech/glide/Registry.java b/library/src/main/java/com/bumptech/glide/Registry.java
index 41e4c84327..49d31b6f7a 100644
--- a/library/src/main/java/com/bumptech/glide/Registry.java
+++ b/library/src/main/java/com/bumptech/glide/Registry.java
@@ -398,8 +398,9 @@ public Registry register(@NonNull ImageHeaderParser parser) {
    * {@link java.io.FileDescriptor}).
    */
   @NonNull
-  public <Model, Data> Registry append(Class<Model> modelClass, Class<Data> dataClass,
-      ModelLoaderFactory<Model, Data> factory) {
+  public <Model, Data> Registry append(
+      @NonNull Class<Model> modelClass, @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<Model, Data> factory) {
     modelLoaderRegistry.append(modelClass, dataClass, factory);
     return this;
   }
@@ -428,8 +429,9 @@ public <Model, Data> Registry append(Class<Model> modelClass, Class<Data> dataCl
    * {@link java.io.FileDescriptor}).
    */
   @NonNull
-  public <Model, Data> Registry prepend(Class<Model> modelClass, Class<Data> dataClass,
-      ModelLoaderFactory<Model, Data> factory) {
+  public <Model, Data> Registry prepend(
+      @NonNull Class<Model> modelClass, @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<Model, Data> factory) {
     modelLoaderRegistry.prepend(modelClass, dataClass, factory);
     return this;
   }
@@ -459,9 +461,9 @@ public <Model, Data> Registry prepend(Class<Model> modelClass, Class<Data> dataC
    */
   @NonNull
   public <Model, Data> Registry replace(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     modelLoaderRegistry.replace(modelClass, dataClass, factory);
     return this;
   }
@@ -518,7 +520,7 @@ private <Data, TResource, Transcode> List<DecodePath<Data, TResource, Transcode>
 
   @Nullable
   public <Model, TResource, Transcode> List<Class<?>> getRegisteredResourceClasses(
-      Class<Model> modelClass, @NonNull Class<TResource> resourceClass,
+      @NonNull Class<Model> modelClass, @NonNull Class<TResource> resourceClass,
       @NonNull Class<Transcode> transcodeClass) {
     List<Class<?>> result = modelToResourceClassCache.get(modelClass, resourceClass);
 
@@ -597,11 +599,12 @@ public List<ImageHeaderParser> getImageHeaderParsers() {
   // Never serialized by Glide.
   @SuppressWarnings("serial")
   public static class NoModelLoaderAvailableException extends MissingComponentException {
-    public NoModelLoaderAvailableException(Object model) {
+    public NoModelLoaderAvailableException(@NonNull Object model) {
       super("Failed to find any ModelLoaders for model: " + model);
     }
 
-    public NoModelLoaderAvailableException(Class<?> modelClass, Class<?> dataClass) {
+    public NoModelLoaderAvailableException(@NonNull Class<?> modelClass,
+        @NonNull Class<?> dataClass) {
       super("Failed to find any ModelLoaders for model: " + modelClass + " and data: " + dataClass);
     }
   }
@@ -612,7 +615,7 @@ public NoModelLoaderAvailableException(Class<?> modelClass, Class<?> dataClass)
   // Never serialized by Glide.
   @SuppressWarnings("serial")
   public static class NoResultEncoderAvailableException extends MissingComponentException {
-    public NoResultEncoderAvailableException(Class<?> resourceClass) {
+    public NoResultEncoderAvailableException(@NonNull Class<?> resourceClass) {
       super("Failed to find result encoder for resource class: " + resourceClass);
     }
   }
@@ -623,7 +626,7 @@ public NoResultEncoderAvailableException(Class<?> resourceClass) {
   // Never serialized by Glide.
   @SuppressWarnings("serial")
   public static class NoSourceEncoderAvailableException extends MissingComponentException {
-    public NoSourceEncoderAvailableException(Class<?> dataClass) {
+    public NoSourceEncoderAvailableException(@NonNull Class<?> dataClass) {
       super("Failed to find source encoder for data class: " + dataClass);
     }
   }
@@ -634,7 +637,7 @@ public NoSourceEncoderAvailableException(Class<?> dataClass) {
   // Never serialized by Glide.
   @SuppressWarnings("serial")
   public static class MissingComponentException extends RuntimeException {
-    public MissingComponentException(String message) {
+    public MissingComponentException(@NonNull String message) {
       super(message);
     }
   }
diff --git a/library/src/main/java/com/bumptech/glide/load/data/AssetPathFetcher.java b/library/src/main/java/com/bumptech/glide/load/data/AssetPathFetcher.java
index 863ee034b4..f21eb6c646 100644
--- a/library/src/main/java/com/bumptech/glide/load/data/AssetPathFetcher.java
+++ b/library/src/main/java/com/bumptech/glide/load/data/AssetPathFetcher.java
@@ -27,7 +27,7 @@ public AssetPathFetcher(AssetManager assetManager, String assetPath) {
   }
 
   @Override
-  public void loadData(Priority priority, DataCallback<? super T> callback) {
+  public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super T> callback) {
     try {
       data = loadResource(assetManager, assetPath);
     } catch (IOException e) {
diff --git a/library/src/main/java/com/bumptech/glide/load/data/DataFetcher.java b/library/src/main/java/com/bumptech/glide/load/data/DataFetcher.java
index 9889eaf06f..4a1674fd90 100644
--- a/library/src/main/java/com/bumptech/glide/load/data/DataFetcher.java
+++ b/library/src/main/java/com/bumptech/glide/load/data/DataFetcher.java
@@ -39,7 +39,7 @@ interface DataCallback<T> {
      *
      * @param e a non-null {@link Exception} indicating why the load failed.
      */
-    void onLoadFailed(Exception e);
+    void onLoadFailed(@NonNull Exception e);
   }
 
   /**
@@ -63,7 +63,7 @@ interface DataCallback<T> {
    * @param callback The callback to use when the request is complete
    * @see #cleanup() where the data retuned will be cleaned up
    */
-  void loadData(Priority priority, DataCallback<? super T> callback);
+  void loadData(@NonNull Priority priority, @NonNull DataCallback<? super T> callback);
 
   /**
    * Cleanup or recycle any resources used by this data fetcher. This method will be called in a
diff --git a/library/src/main/java/com/bumptech/glide/load/data/HttpUrlFetcher.java b/library/src/main/java/com/bumptech/glide/load/data/HttpUrlFetcher.java
index 0649266988..d150608b48 100644
--- a/library/src/main/java/com/bumptech/glide/load/data/HttpUrlFetcher.java
+++ b/library/src/main/java/com/bumptech/glide/load/data/HttpUrlFetcher.java
@@ -48,7 +48,8 @@ public HttpUrlFetcher(GlideUrl glideUrl, int timeout) {
   }
 
   @Override
-  public void loadData(Priority priority, DataCallback<? super InputStream> callback) {
+  public void loadData(@NonNull Priority priority,
+      @NonNull DataCallback<? super InputStream> callback) {
     long startTime = LogTime.getLogTime();
     final InputStream result;
     try {
diff --git a/library/src/main/java/com/bumptech/glide/load/data/LocalUriFetcher.java b/library/src/main/java/com/bumptech/glide/load/data/LocalUriFetcher.java
index cb77e05ea8..68ee753057 100644
--- a/library/src/main/java/com/bumptech/glide/load/data/LocalUriFetcher.java
+++ b/library/src/main/java/com/bumptech/glide/load/data/LocalUriFetcher.java
@@ -38,7 +38,8 @@ public LocalUriFetcher(ContentResolver contentResolver, Uri uri) {
   }
 
   @Override
-  public final void loadData(Priority priority, DataCallback<? super T> callback) {
+  public final void loadData(@NonNull Priority priority,
+      @NonNull DataCallback<? super T> callback) {
     try {
       data = loadResource(uri, contentResolver);
     } catch (FileNotFoundException e) {
diff --git a/library/src/main/java/com/bumptech/glide/load/data/mediastore/ThumbFetcher.java b/library/src/main/java/com/bumptech/glide/load/data/mediastore/ThumbFetcher.java
index 3ab7f6a54e..3b90b0a6bf 100644
--- a/library/src/main/java/com/bumptech/glide/load/data/mediastore/ThumbFetcher.java
+++ b/library/src/main/java/com/bumptech/glide/load/data/mediastore/ThumbFetcher.java
@@ -52,7 +52,8 @@ private static ThumbFetcher build(Context context, Uri uri, ThumbnailQuery query
   }
 
   @Override
-  public void loadData(Priority priority, DataCallback<? super InputStream> callback) {
+  public void loadData(@NonNull Priority priority,
+      @NonNull DataCallback<? super InputStream> callback) {
     try {
       inputStream = openThumbInputStream();
     } catch (FileNotFoundException e) {
@@ -117,11 +118,11 @@ static class VideoThumbnailQuery implements ThumbnailQuery {
     }
 
     private static final String[] PATH_PROJECTION = {
-      MediaStore.Video.Thumbnails.DATA
+        MediaStore.Video.Thumbnails.DATA
     };
     private static final String PATH_SELECTION =
         MediaStore.Video.Thumbnails.KIND + " = " + MediaStore.Video.Thumbnails.MINI_KIND
-        + " AND " + MediaStore.Video.Thumbnails.VIDEO_ID + " = ?";
+            + " AND " + MediaStore.Video.Thumbnails.VIDEO_ID + " = ?";
 
     @Override
     public Cursor query(Uri uri) {
@@ -145,11 +146,11 @@ static class ImageThumbnailQuery implements ThumbnailQuery {
     }
 
     private static final String[] PATH_PROJECTION = {
-      MediaStore.Images.Thumbnails.DATA,
+        MediaStore.Images.Thumbnails.DATA,
     };
     private static final String PATH_SELECTION =
         MediaStore.Images.Thumbnails.KIND + " = " + MediaStore.Images.Thumbnails.MINI_KIND
-        + " AND " + MediaStore.Images.Thumbnails.IMAGE_ID + " = ?";
+            + " AND " + MediaStore.Images.Thumbnails.IMAGE_ID + " = ?";
 
     @Override
     public Cursor query(Uri uri) {
diff --git a/library/src/main/java/com/bumptech/glide/load/engine/DataCacheGenerator.java b/library/src/main/java/com/bumptech/glide/load/engine/DataCacheGenerator.java
index 2eb478ee31..0972f30ad5 100644
--- a/library/src/main/java/com/bumptech/glide/load/engine/DataCacheGenerator.java
+++ b/library/src/main/java/com/bumptech/glide/load/engine/DataCacheGenerator.java
@@ -1,5 +1,6 @@
 package com.bumptech.glide.load.engine;
 
+import android.support.annotation.NonNull;
 import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.Key;
 import com.bumptech.glide.load.data.DataFetcher;
@@ -92,7 +93,7 @@ public void onDataReady(Object data) {
   }
 
   @Override
-  public void onLoadFailed(Exception e) {
+  public void onLoadFailed(@NonNull Exception e) {
     cb.onDataFetcherFailed(sourceKey, e, loadData.fetcher, DataSource.DATA_DISK_CACHE);
   }
 }
diff --git a/library/src/main/java/com/bumptech/glide/load/engine/ResourceCacheGenerator.java b/library/src/main/java/com/bumptech/glide/load/engine/ResourceCacheGenerator.java
index 43a446f590..537da858a9 100644
--- a/library/src/main/java/com/bumptech/glide/load/engine/ResourceCacheGenerator.java
+++ b/library/src/main/java/com/bumptech/glide/load/engine/ResourceCacheGenerator.java
@@ -1,5 +1,6 @@
 package com.bumptech.glide.load.engine;
 
+import android.support.annotation.NonNull;
 import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.Key;
 import com.bumptech.glide.load.Transformation;
@@ -110,7 +111,7 @@ public void onDataReady(Object data) {
   }
 
   @Override
-  public void onLoadFailed(Exception e) {
+  public void onLoadFailed(@NonNull Exception e) {
     cb.onDataFetcherFailed(currentKey, e, loadData.fetcher, DataSource.RESOURCE_DISK_CACHE);
   }
 }
diff --git a/library/src/main/java/com/bumptech/glide/load/engine/SourceGenerator.java b/library/src/main/java/com/bumptech/glide/load/engine/SourceGenerator.java
index f95ea8ca2a..5a57b971be 100644
--- a/library/src/main/java/com/bumptech/glide/load/engine/SourceGenerator.java
+++ b/library/src/main/java/com/bumptech/glide/load/engine/SourceGenerator.java
@@ -1,5 +1,6 @@
 package com.bumptech.glide.load.engine;
 
+import android.support.annotation.NonNull;
 import android.util.Log;
 import com.bumptech.glide.load.DataSource;
 import com.bumptech.glide.load.Encoder;
@@ -114,7 +115,7 @@ public void onDataReady(Object data) {
   }
 
   @Override
-  public void onLoadFailed(Exception e) {
+  public void onLoadFailed(@NonNull Exception e) {
     cb.onDataFetcherFailed(originalKey, e, loadData.fetcher, loadData.fetcher.getDataSource());
   }
 
diff --git a/library/src/main/java/com/bumptech/glide/load/model/AssetUriLoader.java b/library/src/main/java/com/bumptech/glide/load/model/AssetUriLoader.java
index f8af6151b0..9eea06323f 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/AssetUriLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/AssetUriLoader.java
@@ -67,6 +67,7 @@ public StreamFactory(AssetManager assetManager) {
       this.assetManager = assetManager;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new AssetUriLoader<>(assetManager, this);
@@ -96,6 +97,7 @@ public FileDescriptorFactory(AssetManager assetManager) {
       this.assetManager = assetManager;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, ParcelFileDescriptor> build(MultiModelLoaderFactory multiFactory) {
       return new AssetUriLoader<>(assetManager, this);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/ByteArrayLoader.java b/library/src/main/java/com/bumptech/glide/load/model/ByteArrayLoader.java
index 54d80326ce..42b17bf235 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/ByteArrayLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/ByteArrayLoader.java
@@ -56,7 +56,7 @@ private static class Fetcher<Data> implements DataFetcher<Data> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super Data> callback) {
+    public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super Data> callback) {
       Data result = converter.convert(model);
       callback.onDataReady(result);
     }
@@ -90,6 +90,7 @@ public DataSource getDataSource() {
    */
   public static class ByteBufferFactory implements ModelLoaderFactory<byte[], ByteBuffer> {
 
+    @NonNull
     @Override
     public ModelLoader<byte[], ByteBuffer> build(MultiModelLoaderFactory multiFactory) {
       return new ByteArrayLoader<>(new Converter<ByteBuffer>() {
@@ -116,6 +117,7 @@ public void teardown() {
    */
   public static class StreamFactory implements ModelLoaderFactory<byte[], InputStream> {
 
+    @NonNull
     @Override
     public ModelLoader<byte[], InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new ByteArrayLoader<>(new Converter<InputStream>() {
diff --git a/library/src/main/java/com/bumptech/glide/load/model/ByteBufferFileLoader.java b/library/src/main/java/com/bumptech/glide/load/model/ByteBufferFileLoader.java
index bc0ac5dc5d..213c25ce18 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/ByteBufferFileLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/ByteBufferFileLoader.java
@@ -35,6 +35,7 @@ public boolean handles(@NonNull File file) {
    */
   public static class Factory implements ModelLoaderFactory<File, ByteBuffer> {
 
+    @NonNull
     @Override
     public ModelLoader<File, ByteBuffer> build(MultiModelLoaderFactory multiFactory) {
       return new ByteBufferFileLoader();
@@ -57,7 +58,8 @@ private static class ByteBufferFetcher implements DataFetcher<ByteBuffer> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super ByteBuffer> callback) {
+    public void loadData(@NonNull Priority priority,
+        @NonNull DataCallback<? super ByteBuffer> callback) {
       ByteBuffer result;
       try {
         result = ByteBufferUtil.fromFile(file);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/DataUrlLoader.java b/library/src/main/java/com/bumptech/glide/load/model/DataUrlLoader.java
index 8a47e2068e..6865bb818e 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/DataUrlLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/DataUrlLoader.java
@@ -71,7 +71,7 @@ private static final class DataUriFetcher<Data> implements DataFetcher<Data> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super Data> callback) {
+    public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super Data> callback) {
       try {
         data = reader.decode(dataUri);
         callback.onDataReady(data);
@@ -150,6 +150,7 @@ public Class<InputStream> getDataClass() {
       };
     }
 
+    @NonNull
     @Override
     public final ModelLoader<String, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new DataUrlLoader<>(opener);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/FileLoader.java b/library/src/main/java/com/bumptech/glide/load/model/FileLoader.java
index 0e1b732b2f..f56f8bd589 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/FileLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/FileLoader.java
@@ -63,7 +63,7 @@ private static class FileFetcher<Data> implements DataFetcher<Data> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super Data> callback) {
+    public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super Data> callback) {
       try {
         data = opener.open(file);
       } catch (FileNotFoundException e) {
@@ -116,6 +116,7 @@ public Factory(FileOpener<Data> opener) {
       this.opener = opener;
     }
 
+    @NonNull
     @Override
     public final ModelLoader<File, Data> build(MultiModelLoaderFactory multiFactory) {
       return new FileLoader<>(opener);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/MediaStoreFileLoader.java b/library/src/main/java/com/bumptech/glide/load/model/MediaStoreFileLoader.java
index 32867b9283..6b36fb0ecb 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/MediaStoreFileLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/MediaStoreFileLoader.java
@@ -53,7 +53,7 @@ private static class FilePathFetcher implements DataFetcher<File> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super File> callback) {
+    public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super File> callback) {
       Cursor cursor = context.getContentResolver().query(uri, PROJECTION, null /*selection*/,
           null /*selectionArgs*/, null /*sortOrder*/);
 
@@ -109,6 +109,7 @@ public Factory(Context context) {
       this.context = context;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, File> build(MultiModelLoaderFactory multiFactory) {
       return new MediaStoreFileLoader(context);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/ModelLoader.java b/library/src/main/java/com/bumptech/glide/load/model/ModelLoader.java
index 30fde57fd8..2ef8de0dc4 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/ModelLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/ModelLoader.java
@@ -47,11 +47,12 @@ class LoadData<Data> {
     public final List<Key> alternateKeys;
     public final DataFetcher<Data> fetcher;
 
-    public LoadData(Key sourceKey, DataFetcher<Data> fetcher) {
+    public LoadData(@NonNull Key sourceKey, @NonNull DataFetcher<Data> fetcher) {
       this(sourceKey, Collections.<Key>emptyList(), fetcher);
     }
 
-    public LoadData(Key sourceKey, List<Key> alternateKeys, DataFetcher<Data> fetcher) {
+    public LoadData(@NonNull Key sourceKey, @NonNull List<Key> alternateKeys,
+        @NonNull DataFetcher<Data> fetcher) {
       this.sourceKey = Preconditions.checkNotNull(sourceKey);
       this.alternateKeys = Preconditions.checkNotNull(alternateKeys);
       this.fetcher = Preconditions.checkNotNull(fetcher);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderFactory.java b/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderFactory.java
index 19e1260195..3210771441 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderFactory.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderFactory.java
@@ -1,6 +1,7 @@
 package com.bumptech.glide.load.model;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 /**
  * An interface for creating a {@link ModelLoader} for a given model type. Will be retained
@@ -22,7 +23,8 @@ public interface ModelLoaderFactory<T, Y> {
    *                     {@link ModelLoader}s that this factory's {@link ModelLoader} may depend on
    * @return A new {@link ModelLoader}
    */
-  ModelLoader<T, Y> build(MultiModelLoaderFactory multiFactory);
+  @NonNull
+  ModelLoader<T, Y> build(@NonNull MultiModelLoaderFactory multiFactory);
 
   /**
    * A lifecycle method that will be called when this factory is about to replaced.
diff --git a/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderRegistry.java b/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderRegistry.java
index 37497b9911..ef11d7a211 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderRegistry.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/ModelLoaderRegistry.java
@@ -1,5 +1,7 @@
 package com.bumptech.glide.load.model;
 
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.v4.util.Pools.Pool;
 import com.bumptech.glide.util.Synthetic;
 import java.util.ArrayList;
@@ -19,51 +21,53 @@ public class ModelLoaderRegistry {
   private final MultiModelLoaderFactory multiModelLoaderFactory;
   private final ModelLoaderCache cache = new ModelLoaderCache();
 
-  public ModelLoaderRegistry(Pool<List<Throwable>> throwableListPool) {
+  public ModelLoaderRegistry(@NonNull Pool<List<Throwable>> throwableListPool) {
     this(new MultiModelLoaderFactory(throwableListPool));
   }
 
-  private ModelLoaderRegistry(MultiModelLoaderFactory multiModelLoaderFactory) {
+  private ModelLoaderRegistry(@NonNull MultiModelLoaderFactory multiModelLoaderFactory) {
     this.multiModelLoaderFactory = multiModelLoaderFactory;
   }
 
   public synchronized <Model, Data> void append(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     multiModelLoaderFactory.append(modelClass, dataClass, factory);
     cache.clear();
   }
 
   public synchronized <Model, Data> void prepend(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     multiModelLoaderFactory.prepend(modelClass, dataClass, factory);
     cache.clear();
   }
 
-  public synchronized <Model, Data> void remove(Class<Model> modelClass, Class<Data> dataClass) {
+  public synchronized <Model, Data> void remove(@NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass) {
     tearDown(multiModelLoaderFactory.remove(modelClass, dataClass));
     cache.clear();
   }
 
   public synchronized <Model, Data> void replace(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     tearDown(multiModelLoaderFactory.replace(modelClass, dataClass, factory));
     cache.clear();
   }
 
   private <Model, Data> void tearDown(
-      List<ModelLoaderFactory<? extends Model, ? extends Data>> factories) {
+      @NonNull List<ModelLoaderFactory<? extends Model, ? extends Data>> factories) {
     for (ModelLoaderFactory<? extends Model, ? extends Data> factory : factories) {
       factory.teardown();
     }
   }
 
-  public synchronized <A> List<ModelLoader<A, ?>> getModelLoaders(A model) {
+  @NonNull
+  public synchronized <A> List<ModelLoader<A, ?>> getModelLoaders(@NonNull A model) {
     List<ModelLoader<A, ?>> modelLoaders = getModelLoadersForClass(getClass(model));
     int size = modelLoaders.size();
     List<ModelLoader<A, ?>> filteredLoaders = new ArrayList<>(size);
@@ -77,16 +81,18 @@ private <Model, Data> void tearDown(
     return filteredLoaders;
   }
 
-  public synchronized <Model, Data> ModelLoader<Model, Data> build(Class<Model> modelClass,
-      Class<Data> dataClass) {
+  public synchronized <Model, Data> ModelLoader<Model, Data> build(@NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass) {
     return multiModelLoaderFactory.build(modelClass, dataClass);
   }
 
-  public synchronized List<Class<?>> getDataClasses(Class<?> modelClass) {
+  @NonNull
+  public synchronized List<Class<?>> getDataClasses(@NonNull Class<?> modelClass) {
     return multiModelLoaderFactory.getDataClasses(modelClass);
   }
 
-  private <A> List<ModelLoader<A, ?>> getModelLoadersForClass(Class<A> modelClass) {
+  @NonNull
+  private <A> List<ModelLoader<A, ?>> getModelLoadersForClass(@NonNull Class<A> modelClass) {
     List<ModelLoader<A, ?>> loaders = cache.get(modelClass);
     if (loaders == null) {
       loaders = Collections.unmodifiableList(multiModelLoaderFactory.build(modelClass));
@@ -95,8 +101,9 @@ public synchronized List<Class<?>> getDataClasses(Class<?> modelClass) {
     return loaders;
   }
 
+  @NonNull
   @SuppressWarnings("unchecked")
-  private static <A> Class<A> getClass(A model) {
+  private static <A> Class<A> getClass(@NonNull A model) {
     return (Class<A>) model.getClass();
   }
 
@@ -117,6 +124,7 @@ public <Model> void put(Class<Model> modelClass, List<ModelLoader<Model, ?>> loa
       }
     }
 
+    @Nullable
     @SuppressWarnings("unchecked")
     public <Model> List<ModelLoader<Model, ?>> get(Class<Model> modelClass) {
       Entry<Model> entry = (Entry<Model>) cachedModelLoaders.get(modelClass);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoader.java b/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoader.java
index 84d97b2cac..684dc76b00 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoader.java
@@ -29,8 +29,8 @@ class MultiModelLoader<Model, Data> implements ModelLoader<Model, Data> {
   private final List<ModelLoader<Model, Data>> modelLoaders;
   private final Pool<List<Throwable>> exceptionListPool;
 
-  MultiModelLoader(List<ModelLoader<Model, Data>> modelLoaders,
-      Pool<List<Throwable>> exceptionListPool) {
+  MultiModelLoader(@NonNull List<ModelLoader<Model, Data>> modelLoaders,
+      @NonNull Pool<List<Throwable>> exceptionListPool) {
     this.modelLoaders = modelLoaders;
     this.exceptionListPool = exceptionListPool;
   }
@@ -82,7 +82,8 @@ static class MultiFetcher<Data> implements DataFetcher<Data>, DataCallback<Data>
     @Nullable
     private List<Throwable> exceptions;
 
-    MultiFetcher(List<DataFetcher<Data>> fetchers, Pool<List<Throwable>> throwableListPool) {
+    MultiFetcher(@NonNull List<DataFetcher<Data>> fetchers,
+        @NonNull Pool<List<Throwable>> throwableListPool) {
       this.throwableListPool = throwableListPool;
       Preconditions.checkNotEmpty(fetchers);
       this.fetchers = fetchers;
@@ -90,7 +91,7 @@ static class MultiFetcher<Data> implements DataFetcher<Data>, DataCallback<Data>
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super Data> callback) {
+    public void loadData(@NonNull Priority priority, @NonNull DataCallback<? super Data> callback) {
       this.priority = priority;
       this.callback = callback;
       exceptions = throwableListPool.acquire();
@@ -128,7 +129,7 @@ public DataSource getDataSource() {
     }
 
     @Override
-    public void onDataReady(Data data) {
+    public void onDataReady(@Nullable Data data) {
       if (data != null) {
         callback.onDataReady(data);
       } else {
@@ -137,7 +138,7 @@ public void onDataReady(Data data) {
     }
 
     @Override
-    public void onLoadFailed(Exception e) {
+    public void onLoadFailed(@NonNull Exception e) {
       Preconditions.checkNotNull(exceptions).add(e);
       startNextOrFail();
     }
diff --git a/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoaderFactory.java b/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoaderFactory.java
index eb903fab35..a286bc09da 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoaderFactory.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/MultiModelLoaderFactory.java
@@ -28,53 +28,55 @@ public class MultiModelLoaderFactory {
   private final Set<Entry<?, ?>> alreadyUsedEntries = new HashSet<>();
   private final Pool<List<Throwable>> throwableListPool;
 
-  public MultiModelLoaderFactory(Pool<List<Throwable>> throwableListPool) {
+  public MultiModelLoaderFactory(@NonNull Pool<List<Throwable>> throwableListPool) {
     this(throwableListPool, DEFAULT_FACTORY);
   }
 
   @VisibleForTesting
-  MultiModelLoaderFactory(Pool<List<Throwable>> throwableListPool,
-      Factory factory) {
+  MultiModelLoaderFactory(@NonNull Pool<List<Throwable>> throwableListPool,
+      @NonNull Factory factory) {
     this.throwableListPool = throwableListPool;
     this.factory = factory;
   }
 
   synchronized <Model, Data> void append(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     add(modelClass, dataClass, factory, /*append=*/ true);
   }
 
   synchronized <Model, Data> void prepend(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     add(modelClass, dataClass, factory, /*append=*/ false);
   }
 
   private <Model, Data> void add(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory,
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory,
       boolean append) {
     Entry<Model, Data> entry = new Entry<>(modelClass, dataClass, factory);
     entries.add(append ? entries.size() : 0, entry);
   }
 
+  @NonNull
   synchronized <Model, Data> List<ModelLoaderFactory<? extends Model, ? extends Data>> replace(
-      Class<Model> modelClass,
-      Class<Data> dataClass,
-      ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass,
+      @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
     List<ModelLoaderFactory<? extends Model, ? extends Data>> removed =
         remove(modelClass, dataClass);
     append(modelClass, dataClass, factory);
     return removed;
   }
 
+  @NonNull
   synchronized <Model, Data> List<ModelLoaderFactory<? extends Model, ? extends Data>> remove(
-      Class<Model> modelClass,
-      Class<Data> dataClass) {
+      @NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass) {
     List<ModelLoaderFactory<? extends Model, ? extends Data>> factories = new ArrayList<>();
     for (Iterator<Entry<?, ?>> iterator = entries.iterator(); iterator.hasNext(); ) {
       Entry<?, ?> entry = iterator.next();
@@ -86,7 +88,8 @@ private <Model, Data> void add(
     return factories;
   }
 
-  synchronized <Model> List<ModelLoader<Model, ?>> build(Class<Model> modelClass) {
+  @NonNull
+  synchronized <Model> List<ModelLoader<Model, ?>> build(@NonNull Class<Model> modelClass) {
     try {
       List<ModelLoader<Model, ?>> loaders = new ArrayList<>();
       for (Entry<?, ?> entry : entries) {
@@ -111,7 +114,8 @@ private <Model, Data> void add(
     }
   }
 
-  synchronized List<Class<?>> getDataClasses(Class<?> modelClass) {
+  @NonNull
+  synchronized List<Class<?>> getDataClasses(@NonNull Class<?> modelClass) {
     List<Class<?>> result = new ArrayList<>();
     for (Entry<?, ?> entry : entries) {
       if (!result.contains(entry.dataClass) && entry.handles(modelClass)) {
@@ -121,8 +125,9 @@ synchronized List<Class<?>> getDataClasses(Class<?> modelClass) {
     return result;
   }
 
-  public synchronized <Model, Data> ModelLoader<Model, Data> build(Class<Model> modelClass,
-      Class<Data> dataClass) {
+  @NonNull
+  public synchronized <Model, Data> ModelLoader<Model, Data> build(@NonNull Class<Model> modelClass,
+      @NonNull Class<Data> dataClass) {
     try {
       List<ModelLoader<Model, Data>> loaders = new ArrayList<>();
       boolean ignoredAnyEntries = false;
@@ -162,16 +167,19 @@ public synchronized <Model, Data> ModelLoader<Model, Data> build(Class<Model> mo
     }
   }
 
+  @NonNull
   @SuppressWarnings("unchecked")
-  private <Model, Data> ModelLoaderFactory<Model, Data> getFactory(Entry<?, ?> entry) {
+  private <Model, Data> ModelLoaderFactory<Model, Data> getFactory(@NonNull Entry<?, ?> entry) {
     return (ModelLoaderFactory<Model, Data>) entry.factory;
   }
 
+  @NonNull
   @SuppressWarnings("unchecked")
-  private <Model, Data> ModelLoader<Model, Data> build(Entry<?, ?> entry) {
+  private <Model, Data> ModelLoader<Model, Data> build(@NonNull Entry<?, ?> entry) {
     return (ModelLoader<Model, Data>) Preconditions.checkNotNull(entry.factory.build(this));
   }
 
+  @NonNull
   @SuppressWarnings("unchecked")
   private static <Model, Data> ModelLoader<Model, Data> emptyModelLoader() {
     return (ModelLoader<Model, Data>) EMPTY_MODEL_LOADER;
@@ -183,32 +191,33 @@ private static class Entry<Model, Data> {
     @Synthetic final ModelLoaderFactory<? extends Model, ? extends Data> factory;
 
     public Entry(
-        Class<Model> modelClass,
-        Class<Data> dataClass,
-        ModelLoaderFactory<? extends Model, ? extends Data> factory) {
+        @NonNull Class<Model> modelClass,
+        @NonNull Class<Data> dataClass,
+        @NonNull ModelLoaderFactory<? extends Model, ? extends Data> factory) {
       this.modelClass = modelClass;
       this.dataClass = dataClass;
       this.factory = factory;
     }
 
-    public boolean handles(Class<?> modelClass, Class<?> dataClass) {
+    public boolean handles(@NonNull Class<?> modelClass, @NonNull Class<?> dataClass) {
       return handles(modelClass) && this.dataClass.isAssignableFrom(dataClass);
     }
 
-    public boolean handles(Class<?> modelClass) {
+    public boolean handles(@NonNull Class<?> modelClass) {
       return this.modelClass.isAssignableFrom(modelClass);
     }
   }
 
   static class Factory {
+    @NonNull
     public <Model, Data> MultiModelLoader<Model, Data> build(
-        List<ModelLoader<Model, Data>> modelLoaders, Pool<List<Throwable>> throwableListPool) {
+        @NonNull List<ModelLoader<Model, Data>> modelLoaders,
+        @NonNull Pool<List<Throwable>> throwableListPool) {
       return new MultiModelLoader<>(modelLoaders, throwableListPool);
     }
   }
 
   private static class EmptyModelLoader implements ModelLoader<Object, Object> {
-
     @Synthetic
     EmptyModelLoader() { }
 
diff --git a/library/src/main/java/com/bumptech/glide/load/model/ResourceLoader.java b/library/src/main/java/com/bumptech/glide/load/model/ResourceLoader.java
index 7d1e491537..5ede18bb80 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/ResourceLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/ResourceLoader.java
@@ -67,6 +67,7 @@ public StreamFactory(Resources resources) {
       this.resources = resources;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Integer, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new ResourceLoader<>(resources, multiFactory.build(Uri.class, InputStream.class));
@@ -90,6 +91,7 @@ public FileDescriptorFactory(Resources resources) {
       this.resources = resources;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Integer, ParcelFileDescriptor> build(MultiModelLoaderFactory multiFactory) {
       return new ResourceLoader<>(
@@ -113,6 +115,7 @@ public UriFactory(Resources resources) {
       this.resources = resources;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Integer, Uri> build(MultiModelLoaderFactory multiFactory) {
       return new ResourceLoader<>(resources, UnitModelLoader.<Uri>getInstance());
diff --git a/library/src/main/java/com/bumptech/glide/load/model/StringLoader.java b/library/src/main/java/com/bumptech/glide/load/model/StringLoader.java
index 85425979c5..26e2c95ecf 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/StringLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/StringLoader.java
@@ -62,6 +62,7 @@ private static Uri toFileUri(String path) {
    */
   public static class StreamFactory implements ModelLoaderFactory<String, InputStream> {
 
+    @NonNull
     @Override
     public ModelLoader<String, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new StringLoader<>(multiFactory.build(Uri.class, InputStream.class));
@@ -79,6 +80,7 @@ public void teardown() {
   public static class FileDescriptorFactory
       implements ModelLoaderFactory<String, ParcelFileDescriptor> {
 
+    @NonNull
     @Override
     public ModelLoader<String, ParcelFileDescriptor> build(MultiModelLoaderFactory multiFactory) {
       return new StringLoader<>(multiFactory.build(Uri.class, ParcelFileDescriptor.class));
diff --git a/library/src/main/java/com/bumptech/glide/load/model/UnitModelLoader.java b/library/src/main/java/com/bumptech/glide/load/model/UnitModelLoader.java
index c59f2dd0aa..4ca9dd16a7 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/UnitModelLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/UnitModelLoader.java
@@ -50,7 +50,8 @@ private static class UnitFetcher<Model> implements DataFetcher<Model> {
     }
 
     @Override
-    public void loadData(Priority priority, DataCallback<? super Model> callback) {
+    public void loadData(@NonNull Priority priority,
+        @NonNull DataCallback<? super Model> callback) {
       callback.onDataReady(resource);
     }
 
@@ -100,6 +101,7 @@ public Factory() {
       // Intentionally empty.
     }
 
+    @NonNull
     @Override
     public ModelLoader<Model, Model> build(MultiModelLoaderFactory multiFactory) {
       return UnitModelLoader.getInstance();
diff --git a/library/src/main/java/com/bumptech/glide/load/model/UriLoader.java b/library/src/main/java/com/bumptech/glide/load/model/UriLoader.java
index 51277b4414..3b02a4902c 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/UriLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/UriLoader.java
@@ -79,6 +79,7 @@ public DataFetcher<InputStream> build(Uri uri) {
       return new StreamLocalUriFetcher(contentResolver, uri);
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new UriLoader<>(this);
@@ -108,6 +109,7 @@ public DataFetcher<ParcelFileDescriptor> build(Uri uri) {
       return new FileDescriptorLocalUriFetcher(contentResolver, uri);
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, ParcelFileDescriptor> build(MultiModelLoaderFactory multiFactory) {
       return new UriLoader<>(this);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/UrlUriLoader.java b/library/src/main/java/com/bumptech/glide/load/model/UrlUriLoader.java
index 931ac86494..f51b8698f8 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/UrlUriLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/UrlUriLoader.java
@@ -50,6 +50,7 @@ public boolean handles(@NonNull Uri uri) {
    */
   public static class StreamFactory implements ModelLoaderFactory<Uri, InputStream> {
 
+    @NonNull
     @Override
     public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new UrlUriLoader<>(multiFactory.build(GlideUrl.class, InputStream.class));
diff --git a/library/src/main/java/com/bumptech/glide/load/model/stream/HttpGlideUrlLoader.java b/library/src/main/java/com/bumptech/glide/load/model/stream/HttpGlideUrlLoader.java
index 90bfbcc6fe..e149e19167 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/stream/HttpGlideUrlLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/stream/HttpGlideUrlLoader.java
@@ -66,6 +66,7 @@ public boolean handles(@NonNull GlideUrl model) {
   public static class Factory implements ModelLoaderFactory<GlideUrl, InputStream> {
     private final ModelCache<GlideUrl, GlideUrl> modelCache = new ModelCache<>(500);
 
+    @NonNull
     @Override
     public ModelLoader<GlideUrl, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new HttpGlideUrlLoader(modelCache);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/stream/HttpUriLoader.java b/library/src/main/java/com/bumptech/glide/load/model/stream/HttpUriLoader.java
index 0567509267..7ff6639b20 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/stream/HttpUriLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/stream/HttpUriLoader.java
@@ -44,6 +44,7 @@ public boolean handles(@NonNull Uri model) {
    */
   public static class Factory implements ModelLoaderFactory<Uri, InputStream> {
 
+    @NonNull
     @Override
     public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new HttpUriLoader(multiFactory.build(GlideUrl.class, InputStream.class));
diff --git a/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreImageThumbLoader.java b/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreImageThumbLoader.java
index fdce945ade..aba0fe3cfa 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreImageThumbLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreImageThumbLoader.java
@@ -51,6 +51,7 @@ public Factory(Context context) {
       this.context = context;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new MediaStoreImageThumbLoader(context);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreVideoThumbLoader.java b/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreVideoThumbLoader.java
index a2862cf02c..678961ed0e 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreVideoThumbLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/stream/MediaStoreVideoThumbLoader.java
@@ -65,6 +65,7 @@ public Factory(Context context) {
       this.context = context;
     }
 
+    @NonNull
     @Override
     public ModelLoader<Uri, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new MediaStoreVideoThumbLoader(context);
diff --git a/library/src/main/java/com/bumptech/glide/load/model/stream/UrlLoader.java b/library/src/main/java/com/bumptech/glide/load/model/stream/UrlLoader.java
index a2ae62eff4..c3995affaa 100644
--- a/library/src/main/java/com/bumptech/glide/load/model/stream/UrlLoader.java
+++ b/library/src/main/java/com/bumptech/glide/load/model/stream/UrlLoader.java
@@ -40,6 +40,7 @@ public boolean handles(@NonNull URL model) {
    */
   public static class StreamFactory implements ModelLoaderFactory<URL, InputStream> {
 
+    @NonNull
     @Override
     public ModelLoader<URL, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new UrlLoader(multiFactory.build(GlideUrl.class, InputStream.class));
diff --git a/library/src/main/java/com/bumptech/glide/provider/ModelToResourceClassCache.java b/library/src/main/java/com/bumptech/glide/provider/ModelToResourceClassCache.java
index 076661dfaa..ac417c13f6 100644
--- a/library/src/main/java/com/bumptech/glide/provider/ModelToResourceClassCache.java
+++ b/library/src/main/java/com/bumptech/glide/provider/ModelToResourceClassCache.java
@@ -1,5 +1,6 @@
 package com.bumptech.glide.provider;
 
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.util.ArrayMap;
 import com.bumptech.glide.util.MultiClassKey;
@@ -16,7 +17,7 @@ public class ModelToResourceClassCache {
       new ArrayMap<>();
 
   @Nullable
-  public List<Class<?>> get(Class<?> modelClass, Class<?> resourceClass) {
+  public List<Class<?>> get(@NonNull Class<?> modelClass, @NonNull Class<?> resourceClass) {
     MultiClassKey key = resourceClassKeyRef.getAndSet(null);
     if (key == null) {
       key = new MultiClassKey(modelClass, resourceClass);
@@ -25,13 +26,14 @@ public List<Class<?>> get(Class<?> modelClass, Class<?> resourceClass) {
     }
     final List<Class<?>> result;
     synchronized (registeredResourceClassCache) {
-       result = registeredResourceClassCache.get(key);
+      result = registeredResourceClassCache.get(key);
     }
     resourceClassKeyRef.set(key);
     return result;
   }
 
-  public void put(Class<?> modelClass, Class<?> resourceClass, List<Class<?>> resourceClasses) {
+  public void put(@NonNull Class<?> modelClass, @NonNull Class<?> resourceClass,
+      @NonNull List<Class<?>> resourceClasses) {
     synchronized (registeredResourceClassCache) {
       registeredResourceClassCache
           .put(new MultiClassKey(modelClass, resourceClass), resourceClasses);
diff --git a/library/src/test/java/com/bumptech/glide/load/model/DataUrlLoaderTest.java b/library/src/test/java/com/bumptech/glide/load/model/DataUrlLoaderTest.java
index 6665f07202..f4b3e2d4af 100644
--- a/library/src/test/java/com/bumptech/glide/load/model/DataUrlLoaderTest.java
+++ b/library/src/test/java/com/bumptech/glide/load/model/DataUrlLoaderTest.java
@@ -6,6 +6,7 @@
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.util.Base64;
 import com.bumptech.glide.Priority;
@@ -60,7 +61,7 @@ public class DataUrlLoaderTest {
   private Options options;
 
   @Before
-  public void setUp() throws Exception {
+  public void setUp() {
     MockitoAnnotations.initMocks(this);
     DataUrlLoader.StreamFactory factory = new DataUrlLoader.StreamFactory();
     options = new Options();
@@ -94,7 +95,7 @@ public void testDecode() throws IOException {
   }
 
   @Test
-  public void testDecodeInvalidScheme() throws IOException {
+  public void testDecodeInvalidScheme() {
     fetcher = dataUrlLoader.buildLoadData(INVALID_URL_WRONG_SCHEME1, -1, -1, options).fetcher;
     CallBack callback = new CallBack();
     fetcher.loadData(Priority.HIGH, callback);
@@ -102,7 +103,7 @@ public void testDecodeInvalidScheme() throws IOException {
   }
 
   @Test
-  public void testDecodeMissingComma() throws IOException {
+  public void testDecodeMissingComma() {
     fetcher = dataUrlLoader.buildLoadData(INVALID_URL_MISSING_COMMA, -1, -1, options).fetcher;
     CallBack callback = new CallBack();
     fetcher.loadData(Priority.HIGH, callback);
@@ -110,7 +111,7 @@ public void testDecodeMissingComma() throws IOException {
   }
 
   @Test
-  public void testDecodeWrongEncoding() throws IOException {
+  public void testDecodeWrongEncoding() {
     fetcher = dataUrlLoader.buildLoadData(INVALID_URL_WRONG_ENCODING, -1, -1, options).fetcher;
     CallBack callback = new CallBack();
     fetcher.loadData(Priority.HIGH, callback);
@@ -128,7 +129,7 @@ public void onDataReady(@Nullable Object data) {
     }
 
     @Override
-    public void onLoadFailed(Exception e) {
+    public void onLoadFailed(@NonNull Exception e) {
       this.exception = e;
     }
   }
diff --git a/samples/flickr/src/main/java/com/bumptech/glide/samples/flickr/FlickrModelLoader.java b/samples/flickr/src/main/java/com/bumptech/glide/samples/flickr/FlickrModelLoader.java
index 1d59551014..a2b3d2f6ef 100644
--- a/samples/flickr/src/main/java/com/bumptech/glide/samples/flickr/FlickrModelLoader.java
+++ b/samples/flickr/src/main/java/com/bumptech/glide/samples/flickr/FlickrModelLoader.java
@@ -26,6 +26,7 @@ public final class FlickrModelLoader extends BaseGlideUrlLoader<Photo> {
   public static class Factory implements ModelLoaderFactory<Photo, InputStream> {
     private final ModelCache<Photo, GlideUrl> modelCache = new ModelCache<>(500);
 
+    @NonNull
     @Override
     public ModelLoader<Photo, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new FlickrModelLoader(
diff --git a/samples/giphy/src/main/java/com/bumptech/glide/samples/giphy/GiphyModelLoader.java b/samples/giphy/src/main/java/com/bumptech/glide/samples/giphy/GiphyModelLoader.java
index 5e4a00502e..a0163074e3 100644
--- a/samples/giphy/src/main/java/com/bumptech/glide/samples/giphy/GiphyModelLoader.java
+++ b/samples/giphy/src/main/java/com/bumptech/glide/samples/giphy/GiphyModelLoader.java
@@ -52,6 +52,7 @@ private static int getDifference(Api.GifImage gifImage, int width, int height) {
    * The default factory for {@link com.bumptech.glide.samples.giphy.GiphyModelLoader}s.
    */
   public static final class Factory implements ModelLoaderFactory<GifResult, InputStream> {
+    @NonNull
     @Override
     public ModelLoader<Api.GifResult, InputStream> build(MultiModelLoaderFactory multiFactory) {
       return new GiphyModelLoader(multiFactory.build(GlideUrl.class, InputStream.class));