diff --git a/demos/cast/src/main/java/com/google/android/exoplayer2/castdemo/package-info.java b/demos/cast/src/main/java/com/google/android/exoplayer2/castdemo/package-info.java
new file mode 100644
index 0000000000..70e2af79df
--- /dev/null
+++ b/demos/cast/src/main/java/com/google/android/exoplayer2/castdemo/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.castdemo;
+
+import com.google.android.exoplayer2.util.NonNullApi;
diff --git a/demos/gl/src/main/java/com/google/android/exoplayer2/gldemo/package-info.java b/demos/gl/src/main/java/com/google/android/exoplayer2/gldemo/package-info.java
new file mode 100644
index 0000000000..59ad052449
--- /dev/null
+++ b/demos/gl/src/main/java/com/google/android/exoplayer2/gldemo/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.gldemo;
+
+import com.google.android.exoplayer2.util.NonNullApi;
diff --git a/demos/main/src/main/java/com/google/android/exoplayer2/demo/package-info.java b/demos/main/src/main/java/com/google/android/exoplayer2/demo/package-info.java
new file mode 100644
index 0000000000..cc22be27e0
--- /dev/null
+++ b/demos/main/src/main/java/com/google/android/exoplayer2/demo/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.demo;
+
+import com.google.android.exoplayer2.util.NonNullApi;
diff --git a/demos/surface/src/main/java/com/google/android/exoplayer2/surfacedemo/package-info.java b/demos/surface/src/main/java/com/google/android/exoplayer2/surfacedemo/package-info.java
new file mode 100644
index 0000000000..0f632a6e3c
--- /dev/null
+++ b/demos/surface/src/main/java/com/google/android/exoplayer2/surfacedemo/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.surfacedemo;
+
+import com.google.android.exoplayer2.util.NonNullApi;
diff --git a/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/package-info.java b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/package-info.java
new file mode 100644
index 0000000000..801f3c4bb5
--- /dev/null
+++ b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/gts/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.playbacktests.gts;
+
+import com.google.android.exoplayer2.util.NonNullApi;
diff --git a/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/hls/package-info.java b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/hls/package-info.java
new file mode 100644
index 0000000000..f971323c6e
--- /dev/null
+++ b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/hls/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.playbacktests.hls;
+
+import com.google.android.exoplayer2.util.NonNullApi;
diff --git a/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/package-info.java b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/package-info.java
new file mode 100644
index 0000000000..4131ced72a
--- /dev/null
+++ b/playbacktests/src/androidTest/java/com/google/android/exoplayer2/playbacktests/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.playbacktests;
+
+import com.google.android.exoplayer2.util.NonNullApi;