Fix a bunch of warnings in VDM Demo apps.

 - Reduce ImmutableSet/List usage as it's not supported
   well in Android.
 - Method invocation ... may produce NPE
 - Missing nullability annotations

Fix: 314478048
Test: manual
Change-Id: I7920471b0320144467054ee540d246ebe8c6c4cc

18 files changed, 97 insertions, 105 deletions

diff --git a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayAdapter.java b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayAdapter.java
index e3376cdcf..730e73d83 100644
--- a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayAdapter.java
+++ b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayAdapter.java
@@ -41,6 +41,7 @@ import com.example.android.vdmdemo.common.RemoteIo;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 import java.util.concurrent.atomic.AtomicInteger;
 
 final class DisplayAdapter extends RecyclerView.Adapter<DisplayHolder> {
@@ -161,7 +162,7 @@ final class DisplayAdapter extends RecyclerView.Adapter<DisplayHolder> {
             mRotateButton.setEnabled(rotationDegrees == 0 || resize);
 
             // Make sure the rotation is visible.
-            View strut = itemView.findViewById(R.id.strut);
+            View strut = itemView.requireViewById(R.id.strut);
             ViewGroup.LayoutParams layoutParams = strut.getLayoutParams();
             layoutParams.width = Math.max(mTextureView.getWidth(), mTextureView.getHeight());
             strut.setLayoutParams(layoutParams);
@@ -220,16 +221,16 @@ final class DisplayAdapter extends RecyclerView.Adapter<DisplayHolder> {
             Log.v(TAG, "Binding DisplayHolder for display " + mDisplayId + " to position "
                     + position);
 
-            mDisplayTitle = itemView.findViewById(R.id.display_title);
-            mTextureView = itemView.findViewById(R.id.remote_display_view);
+            mDisplayTitle = itemView.requireViewById(R.id.display_title);
+            mTextureView = itemView.requireViewById(R.id.remote_display_view);
+            final View displayHeader = itemView.requireViewById(R.id.display_header);
 
             mFocusListener =
                     focusedDisplayId -> {
-                        View displayFocusIndicator = itemView.findViewById(R.id.display_header);
                         if (focusedDisplayId == mDisplayId) {
-                            displayFocusIndicator.setBackgroundResource(R.drawable.focus_frame);
+                            displayHeader.setBackgroundResource(R.drawable.focus_frame);
                         } else {
-                            displayFocusIndicator.setBackground(null);
+                            displayHeader.setBackground(null);
                         }
                     };
             mInputManager.addFocusListener(mFocusListener);
@@ -239,14 +240,15 @@ final class DisplayAdapter extends RecyclerView.Adapter<DisplayHolder> {
 
             setDisplayTitle("");
 
-            View closeButton = itemView.findViewById(R.id.display_close);
+            View closeButton = itemView.requireViewById(R.id.display_close);
             closeButton.setOnClickListener(
-                    v -> ((DisplayAdapter) getBindingAdapter()).removeDisplay(mDisplayId));
+                    v -> ((DisplayAdapter) Objects.requireNonNull(getBindingAdapter()))
+                            .removeDisplay(mDisplayId));
 
-            View backButton = itemView.findViewById(R.id.display_back);
+            View backButton = itemView.requireViewById(R.id.display_back);
             backButton.setOnClickListener(v -> mInputManager.sendBack(mDisplayId));
 
-            View homeButton = itemView.findViewById(R.id.display_home);
+            View homeButton = itemView.requireViewById(R.id.display_home);
             if (remoteDisplay.isHomeSupported()) {
                 homeButton.setVisibility(View.VISIBLE);
                 homeButton.setOnClickListener(v -> mInputManager.sendHome(mDisplayId));
@@ -254,27 +256,23 @@ final class DisplayAdapter extends RecyclerView.Adapter<DisplayHolder> {
                 homeButton.setVisibility(View.GONE);
             }
 
-            mRotateButton = itemView.findViewById(R.id.display_rotate);
-            mRotateButton.setOnClickListener(
-                    v -> {
-                        // This rotation is simply resizing the display with width with height
-                        // swapped.
-                        mDisplayController.setSurface(
-                                mSurface,
-                                /* width= */ mTextureView.getHeight(),
-                                /* height= */ mTextureView.getWidth());
-                        rotateDisplay(
-                                mTextureView.getWidth() > mTextureView.getHeight() ? 90 : -90,
-                                true);
-                    });
+            mRotateButton = itemView.requireViewById(R.id.display_rotate);
+            mRotateButton.setOnClickListener(v -> {
+                // This rotation is simply resizing the display with width with height swapped.
+                mDisplayController.setSurface(
+                        mSurface,
+                        /* width= */ mTextureView.getHeight(),
+                        /* height= */ mTextureView.getWidth());
+                rotateDisplay(mTextureView.getWidth() > mTextureView.getHeight() ? 90 : -90, true);
+            });
 
-            View resizeButton = itemView.findViewById(R.id.display_resize);
+            View resizeButton = itemView.requireViewById(R.id.display_resize);
             resizeButton.setOnTouchListener((v, event) -> {
                 if (event.getAction() != MotionEvent.ACTION_DOWN) {
                     return false;
                 }
-                int maxSize = itemView.getHeight()
-                        - itemView.findViewById(R.id.display_header).getHeight();
+                int maxSize = itemView.getHeight() - displayHeader.getHeight()
+                        - itemView.getPaddingTop() - itemView.getPaddingBottom();
                 mRecyclerView.startResizing(
                         mTextureView, event, maxSize, DisplayHolder.this::resizeDisplay);
                 return true;
diff --git a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayController.java b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayController.java
index 542bf1332..cf4011f79 100644
--- a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayController.java
+++ b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DisplayController.java
@@ -44,10 +44,6 @@ final class DisplayController {
         mDpi = dpi;
     }
 
-    int getDpi() {
-        return mDpi;
-    }
-
     void close() {
         mRemoteIo.sendMessage(
                 RemoteEvent.newBuilder()
diff --git a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DpadFragment.java b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DpadFragment.java
index 878d750ff..867bd15cd 100644
--- a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DpadFragment.java
+++ b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/DpadFragment.java
@@ -54,7 +54,7 @@ public final class DpadFragment extends Hilt_DpadFragment {
         // Set the callback for all the buttons
         // Note: the onClick XML attribute cannot be used with fragments, only activities.
         for (int buttonId : BUTTONS) {
-            ImageButton button = view.findViewById(buttonId);
+            ImageButton button = view.requireViewById(buttonId);
             button.setOnTouchListener(this::onDpadButtonClick);
         }
 
diff --git a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/ImmersiveActivity.java b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/ImmersiveActivity.java
index 8841c0515..6da311e4b 100644
--- a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/ImmersiveActivity.java
+++ b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/ImmersiveActivity.java
@@ -97,7 +97,7 @@ public class ImmersiveActivity extends Hilt_ImmersiveActivity {
         mDisplayController = new DisplayController(DEFAULT_DISPLAY, mRemoteIo);
         mDisplayController.setDpi((int) (getResources().getDisplayMetrics().density * DIP_TO_DPI));
 
-        TextureView textureView = findViewById(R.id.immersive_surface_view);
+        TextureView textureView = requireViewById(R.id.immersive_surface_view);
         textureView.setOnTouchListener(
                 (v, event) -> {
                     if (event.getDevice().supportsSource(InputDevice.SOURCE_TOUCHSCREEN)) {
diff --git a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/MainActivity.java b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/MainActivity.java
index 9e6246410..6354ef9d8 100644
--- a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/MainActivity.java
+++ b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/MainActivity.java
@@ -86,11 +86,11 @@ public class MainActivity extends Hilt_MainActivity {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_main);
-        Toolbar toolbar = findViewById(R.id.main_tool_bar);
+        Toolbar toolbar = requireViewById(R.id.main_tool_bar);
         toolbar.setOverflowIcon(getDrawable(R.drawable.settings));
         setSupportActionBar(toolbar);
 
-        ClientView displaysView = findViewById(R.id.displays);
+        ClientView displaysView = requireViewById(R.id.displays);
         displaysView.setLayoutManager(
                 new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));
         displaysView.setItemAnimator(null);
@@ -194,12 +194,12 @@ public class MainActivity extends Hilt_MainActivity {
     }
 
     private void onDisplayFocusChange(int displayId) {
-        findViewById(R.id.dpad_fragment_container)
+        requireViewById(R.id.dpad_fragment_container)
                 .setVisibility(
                         mSettings.dpadEnabled && displayId != Display.INVALID_DISPLAY
                                 ? View.VISIBLE
                                 : View.GONE);
-        findViewById(R.id.nav_touchpad_fragment_container)
+        requireViewById(R.id.nav_touchpad_fragment_container)
                 .setVisibility(
                         mSettings.navTouchpadEnabled && displayId != Display.INVALID_DISPLAY
                                 ? View.VISIBLE
diff --git a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/NavTouchpadFragment.java b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/NavTouchpadFragment.java
index 427d01719..b78b9675a 100644
--- a/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/NavTouchpadFragment.java
+++ b/samples/VirtualDeviceManager/client/src/com/example/android/vdmdemo/client/NavTouchpadFragment.java
@@ -43,7 +43,7 @@ public final class NavTouchpadFragment extends Hilt_NavTouchpadFragment {
             LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         View view = inflater.inflate(R.layout.fragment_nav_touchpad, container, false);
 
-        TextView navTouchpad = view.findViewById(R.id.nav_touchpad);
+        TextView navTouchpad = view.requireViewById(R.id.nav_touchpad);
         navTouchpad.setOnTouchListener(
                 (v, event) -> {
                     mInputManager.sendInputEventToFocusedDisplay(
diff --git a/samples/VirtualDeviceManager/common/res/values/strings.xml b/samples/VirtualDeviceManager/common/res/values/strings.xml
index 92eaebd7b..a7278d355 100644
--- a/samples/VirtualDeviceManager/common/res/values/strings.xml
+++ b/samples/VirtualDeviceManager/common/res/values/strings.xml
@@ -3,4 +3,5 @@
     <string name="disconnected" translatable="false">Disconnected</string>
     <string name="connecting" translatable="false">Connecting to %s...</string>
     <string name="connected" translatable="false">Connected to %s</string>
+    <string name="error" translatable="false">Error: %s</string>
 </resources>
diff --git a/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/ConnectivityFragment.java b/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/ConnectivityFragment.java
index a28abfb43..f0660c592 100644
--- a/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/ConnectivityFragment.java
+++ b/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/ConnectivityFragment.java
@@ -16,16 +16,20 @@
 
 package com.example.android.vdmdemo.common;
 
+import android.app.Activity;
 import android.graphics.Color;
 import android.os.Bundle;
 import android.util.TypedValue;
 import android.view.View;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
 
 import dagger.hilt.android.AndroidEntryPoint;
 
+import java.util.Objects;
+
 import javax.inject.Inject;
 
 /** Fragment that holds the connectivity status UI. */
@@ -41,27 +45,22 @@ public final class ConnectivityFragment extends Hilt_ConnectivityFragment {
             new ConnectionManager.ConnectionCallback() {
                 @Override
                 public void onConnecting(String remoteDeviceName) {
-                    updateStatus(
-                            getContext().getString(R.string.connecting, remoteDeviceName),
-                            mDefaultBackgroundColor);
+                    updateStatus(mDefaultBackgroundColor, R.string.connecting, remoteDeviceName);
                 }
 
                 @Override
                 public void onConnected(String remoteDeviceName) {
-                    updateStatus(
-                            getContext().getString(R.string.connected, remoteDeviceName),
-                            Color.GREEN);
+                    updateStatus(Color.GREEN, R.string.connected, remoteDeviceName);
                 }
 
                 @Override
                 public void onDisconnected() {
-                    updateStatus(
-                            getContext().getString(R.string.disconnected), mDefaultBackgroundColor);
+                    updateStatus(mDefaultBackgroundColor, R.string.disconnected);
                 }
 
                 @Override
                 public void onError(String message) {
-                    updateStatus(message, Color.RED);
+                    updateStatus(Color.RED, R.string.error, message);
                 }
             };
 
@@ -70,10 +69,10 @@ public final class ConnectivityFragment extends Hilt_ConnectivityFragment {
     }
 
     @Override
-    public void onViewCreated(View view, Bundle bundle) {
+    public void onViewCreated(@NonNull View view, Bundle bundle) {
         super.onViewCreated(view, bundle);
 
-        mStatus = getActivity().findViewById(R.id.connection_status);
+        mStatus = Objects.requireNonNull(getActivity()).requireViewById(R.id.connection_status);
 
         TypedValue background = new TypedValue();
         getActivity()
@@ -105,9 +104,10 @@ public final class ConnectivityFragment extends Hilt_ConnectivityFragment {
         mConnectionManager.removeConnectionCallback(mConnectionCallback);
     }
 
-    private void updateStatus(String message, int backgroundColor) {
-        getActivity().runOnUiThread(() -> {
-            mStatus.setText(message);
+    private void updateStatus(int backgroundColor, int resId, Object... formatArgs) {
+        Activity activity = Objects.requireNonNull(getActivity());
+        activity.runOnUiThread(() -> {
+            mStatus.setText(activity.getString(resId, formatArgs));
             mStatus.setBackgroundColor(backgroundColor);
         });
     }
diff --git a/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/VideoManager.java b/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/VideoManager.java
index 2bfa60e92..3df356655 100644
--- a/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/VideoManager.java
+++ b/samples/VirtualDeviceManager/common/src/com/example/android/vdmdemo/common/VideoManager.java
@@ -28,6 +28,7 @@ import android.util.Log;
 import android.view.Surface;
 
 import androidx.annotation.GuardedBy;
+import androidx.annotation.NonNull;
 
 import com.example.android.vdmdemo.common.RemoteEventProto.DisplayFrame;
 import com.example.android.vdmdemo.common.RemoteEventProto.RemoteEvent;
@@ -41,6 +42,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;
+import java.util.Objects;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -187,12 +189,13 @@ public class VideoManager {
 
     private final class MediaCodecCallback extends MediaCodec.Callback {
         @Override
-        public void onInputBufferAvailable(MediaCodec codec, int i) {
+        public void onInputBufferAvailable(@NonNull MediaCodec codec, int i) {
             mFreeInputBuffers.add(i);
         }
 
         @Override
-        public void onOutputBufferAvailable(MediaCodec codec, int i, BufferInfo bufferInfo) {
+        public void onOutputBufferAvailable(
+                @NonNull MediaCodec codec, int i, @NonNull BufferInfo bufferInfo) {
             synchronized (mCodecLock) {
                 if (mMediaCodec == null) {
                     return;
@@ -200,7 +203,7 @@ public class VideoManager {
                 if (mMediaCodec.getCodecInfo().isEncoder()) {
                     ByteBuffer buffer = mMediaCodec.getOutputBuffer(i);
                     byte[] data = new byte[bufferInfo.size];
-                    buffer.get(data, bufferInfo.offset, bufferInfo.size);
+                    Objects.requireNonNull(buffer).get(data, bufferInfo.offset, bufferInfo.size);
                     mMediaCodec.releaseOutputBuffer(i, false);
                     if (mRecordEncoderOutput) {
                         mStorageFile.writeOutputFile(data);
@@ -216,10 +219,11 @@ public class VideoManager {
         }
 
         @Override
-        public void onError(MediaCodec mediaCodec, CodecException e) {}
+        public void onError(@NonNull MediaCodec mediaCodec, @NonNull CodecException e) {}
 
         @Override
-        public void onOutputFormatChanged(MediaCodec mediaCodec, MediaFormat mediaFormat) {}
+        public void onOutputFormatChanged(
+                @NonNull MediaCodec mediaCodec, @NonNull MediaFormat mediaFormat) {}
     }
 
     private class DecoderThread extends Thread {
@@ -245,7 +249,7 @@ public class VideoManager {
                         }
                         ByteBuffer inBuffer = mMediaCodec.getInputBuffer(inputBuffer);
                         byte[] data = event.getDisplayFrame().getFrameData().toByteArray();
-                        inBuffer.put(data);
+                        Objects.requireNonNull(inBuffer).put(data);
                         if (mRecordEncoderOutput) {
                             mStorageFile.writeOutputFile(data);
                         }
diff --git a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/LatencyDemoActivity.java b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/LatencyDemoActivity.java
index 49d3858f2..74e613744 100644
--- a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/LatencyDemoActivity.java
+++ b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/LatencyDemoActivity.java
@@ -42,7 +42,7 @@ public final class LatencyDemoActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.latency_demo_activity);
-        View counter = findViewById(R.id.counter);
+        View counter = requireViewById(R.id.counter);
 
         mScheduledFuture =
                 mExecutor.scheduleAtFixedRate(
diff --git a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/RotationDemoActivity.java b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/RotationDemoActivity.java
index b489b8441..07158cba9 100644
--- a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/RotationDemoActivity.java
+++ b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/RotationDemoActivity.java
@@ -35,7 +35,7 @@ public final class RotationDemoActivity extends AppCompatActivity {
     @Override
     public void onResume() {
         super.onResume();
-        ((TextView) findViewById(R.id.current_orientation))
+        ((TextView) requireViewById(R.id.current_orientation))
                 .setText(getString(R.string.current_orientation, getOrientationString()));
     }
 
diff --git a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/SensorDemoActivity.java b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/SensorDemoActivity.java
index 80cde97aa..aada6ac5f 100644
--- a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/SensorDemoActivity.java
+++ b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/SensorDemoActivity.java
@@ -32,6 +32,7 @@ import android.widget.TextView;
 import androidx.appcompat.app.AppCompatActivity;
 
 import java.util.List;
+import java.util.Objects;
 
 /**
  * A minimal activity switching between sensor data from the default device and the virtual devices.
@@ -52,7 +53,7 @@ public final class SensorDemoActivity extends AppCompatActivity implements Senso
 
         setContentView(R.layout.sensor_demo_activity);
 
-        mBeam = findViewById(R.id.beam);
+        mBeam = requireViewById(R.id.beam);
 
         mVirtualDeviceManager = getSystemService(VirtualDeviceManager.class);
         mSensorManager = getSystemService(SensorManager.class);
@@ -75,7 +76,8 @@ public final class SensorDemoActivity extends AppCompatActivity implements Senso
         if (context.getDeviceId() == Context.DEVICE_ID_DEFAULT) {
             deviceName = DEVICE_NAME_DEFAULT;
         } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
-            deviceName = mVirtualDeviceManager.getVirtualDevice(context.getDeviceId()).getName();
+            VirtualDevice device = mVirtualDeviceManager.getVirtualDevice(context.getDeviceId());
+            deviceName = Objects.requireNonNull(device).getName();
         } else {
             for (VirtualDevice virtualDevice : mVirtualDeviceManager.getVirtualDevices()) {
                 if (virtualDevice.getDeviceId() == context.getDeviceId()) {
@@ -84,7 +86,7 @@ public final class SensorDemoActivity extends AppCompatActivity implements Senso
                 }
             }
         }
-        TextView currentDevice = findViewById(R.id.current_device);
+        TextView currentDevice = requireViewById(R.id.current_device);
         currentDevice.setText(context.getString(R.string.current_device, deviceName));
     }
 
@@ -119,6 +121,7 @@ public final class SensorDemoActivity extends AppCompatActivity implements Senso
         updateCurrentDeviceTextView(mDeviceContext);
 
         mSensorManager = mDeviceContext.getSystemService(SensorManager.class);
+        Objects.requireNonNull(mSensorManager);
         Sensor sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
         if (sensor != null) {
             mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_UI);
diff --git a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/VibrationDemoActivity.java b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/VibrationDemoActivity.java
index 4f7da0d18..49fe0d436 100644
--- a/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/VibrationDemoActivity.java
+++ b/samples/VirtualDeviceManager/demos/src/com/example/android/vdmdemo/demos/VibrationDemoActivity.java
@@ -35,6 +35,7 @@ import android.widget.TextView;
 import androidx.appcompat.app.AppCompatActivity;
 
 import java.util.List;
+import java.util.Objects;
 
 /** A minimal activity switching between vibration on the default device and the virtual devices. */
 public final class VibrationDemoActivity extends AppCompatActivity {
@@ -74,7 +75,8 @@ public final class VibrationDemoActivity extends AppCompatActivity {
         if (context.getDeviceId() == Context.DEVICE_ID_DEFAULT) {
             deviceName = DEVICE_NAME_DEFAULT;
         } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.VANILLA_ICE_CREAM) {
-            deviceName = mVirtualDeviceManager.getVirtualDevice(context.getDeviceId()).getName();
+            VirtualDevice device = mVirtualDeviceManager.getVirtualDevice(context.getDeviceId());
+            deviceName = Objects.requireNonNull(device).getName();
         } else {
             for (VirtualDevice virtualDevice : mVirtualDeviceManager.getVirtualDevices()) {
                 if (virtualDevice.getDeviceId() == context.getDeviceId()) {
@@ -83,7 +85,7 @@ public final class VibrationDemoActivity extends AppCompatActivity {
                 }
             }
         }
-        TextView currentDevice = findViewById(R.id.current_device);
+        TextView currentDevice = requireViewById(R.id.current_device);
         currentDevice.setText(context.getString(R.string.current_device, deviceName));
     }
 
diff --git a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/AudioStreamer.java b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/AudioStreamer.java
index a6aeb695d..a6fcb08ed 100644
--- a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/AudioStreamer.java
+++ b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/AudioStreamer.java
@@ -41,7 +41,6 @@ import com.example.android.vdmdemo.common.RemoteEventProto.RemoteEvent;
 import com.example.android.vdmdemo.common.RemoteEventProto.StartAudio;
 import com.example.android.vdmdemo.common.RemoteEventProto.StopAudio;
 import com.example.android.vdmdemo.common.RemoteIo;
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.protobuf.ByteString;
 
@@ -51,8 +50,8 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.Objects;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.stream.Collector;
 import java.util.stream.Collectors;
 
 import javax.inject.Inject;
@@ -201,8 +200,7 @@ final class AudioStreamer implements AutoCloseable {
             // The ghost audio record needs to be kept alive, releasing it would cause
             // destruction of remote submix instances and potential problems when updating the
             // UID-based render policy pointing to the remote submix device.
-            ImmutableList<AudioDeviceInfo> preexistingRemoteSubmixDevices =
-                    getRemoteSubmixDevices();
+            List<AudioDeviceInfo> preexistingRemoteSubmixDevices = getRemoteSubmixDevices();
             mGhostRecord = mAudioPolicy.createAudioRecordSink(audioMix);
             mGhostRecord.startRecording();
             mRemoteSubmixDevice = getNewRemoteSubmixAudioDevice(preexistingRemoteSubmixDevices);
@@ -215,15 +213,15 @@ final class AudioStreamer implements AutoCloseable {
 
     private @Nullable AudioDeviceInfo getNewRemoteSubmixAudioDevice(
             Collection<AudioDeviceInfo> preexistingDevices) {
-        ImmutableSet<String> preexistingAddresses =
+        Set<String> preexistingAddresses =
                 preexistingDevices.stream()
                         .map(AudioDeviceInfo::getAddress)
-                        .collect(toImmutableSet());
+                        .collect(Collectors.toSet());
 
-        ImmutableList<AudioDeviceInfo> newDevices =
+        List<AudioDeviceInfo> newDevices =
                 getRemoteSubmixDevices().stream()
                         .filter(dev -> !preexistingAddresses.contains(dev.getAddress()))
-                        .collect(toImmutableList());
+                        .collect(Collectors.toList());
 
         if (newDevices.size() > 1) {
             Log.e(TAG, "There's more than 1 new remote submix device");
@@ -236,7 +234,7 @@ final class AudioStreamer implements AutoCloseable {
         return getOnlyElement(newDevices);
     }
 
-    public void updateVdmUids(ImmutableSet<Integer> uids) {
+    public void updateVdmUids(Set<Integer> uids) {
         Log.w(TAG, "Updating mixing rule to reroute uids " + uids);
         mHandler.post(
                 () -> {
@@ -263,7 +261,7 @@ final class AudioStreamer implements AutoCloseable {
     // That's inefficient and leads to audio leaks. But this is the most correct way to do this at
     // this time.
     @GuardedBy("mLock")
-    private void updateAudioPolicies(ImmutableSet<Integer> uids) {
+    private void updateAudioPolicies(Set<Integer> uids) {
         // TODO(b/293279299) Use Flagged API
         // if (com.android.media.audio.flags.Flags.FLAG_AUDIO_POLICY_UPDATE_MIXING_RULES_API &&
         // uidAudioMix != null && (!reroutedUids.isEmpty() && !uids.isEmpty())) {
@@ -341,10 +339,10 @@ final class AudioStreamer implements AutoCloseable {
         return builder.build();
     }
 
-    private ImmutableList<AudioDeviceInfo> getRemoteSubmixDevices() {
+    private List<AudioDeviceInfo> getRemoteSubmixDevices() {
         return Arrays.stream(mAudioManager.getDevices(AudioManager.GET_DEVICES_OUTPUTS))
                 .filter(AudioStreamer::deviceIsRemoteSubmixOut)
-                .collect(toImmutableList());
+                .collect(Collectors.toList());
     }
 
     private static boolean deviceIsRemoteSubmixOut(AudioDeviceInfo info) {
@@ -404,12 +402,4 @@ final class AudioStreamer implements AutoCloseable {
             mIsRunning.set(false);
         }
     }
-
-    private static <E> Collector<E, ?, ImmutableList<E>> toImmutableList() {
-        return Collectors.collectingAndThen(Collectors.toList(), ImmutableList::copyOf);
-    }
-
-    private static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {
-        return Collectors.collectingAndThen(Collectors.toList(), ImmutableSet::copyOf);
-    }
 }
diff --git a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/LauncherAdapter.java b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/LauncherAdapter.java
index 31f854ae9..3b159d991 100644
--- a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/LauncherAdapter.java
+++ b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/LauncherAdapter.java
@@ -88,12 +88,12 @@ final class LauncherAdapter extends BaseAdapter {
                     LayoutInflater.from(parent.getContext())
                             .inflate(R.layout.launcher_grid_item, parent, false);
         }
-        ImageView imageView = convertView.findViewById(R.id.app_icon);
+        ImageView imageView = convertView.requireViewById(R.id.app_icon);
         final Drawable background = new ShapeDrawable(new OvalShape());
         imageView.setBackground(background);
         imageView.setImageDrawable(img);
 
-        TextView textView = convertView.findViewById(R.id.app_title);
+        TextView textView = convertView.requireViewById(R.id.app_title);
         textView.setText(ri.loadLabel(mPackageManager));
         textView.setTextColor(mTextColor);
         return convertView;
diff --git a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/MainActivity.java b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/MainActivity.java
index 00327519d..01247ce8d 100644
--- a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/MainActivity.java
+++ b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/MainActivity.java
@@ -91,7 +91,7 @@ public class MainActivity extends Hilt_MainActivity {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_main);
-        Toolbar toolbar = findViewById(R.id.main_tool_bar);
+        Toolbar toolbar = requireViewById(R.id.main_tool_bar);
         toolbar.setOverflowIcon(getDrawable(R.drawable.settings));
         setSupportActionBar(toolbar);
 
diff --git a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/RunningVdmUidsTracker.java b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/RunningVdmUidsTracker.java
index 0dee5c1c4..20505893e 100644
--- a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/RunningVdmUidsTracker.java
+++ b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/RunningVdmUidsTracker.java
@@ -26,14 +26,13 @@ import android.util.Log;
 import androidx.annotation.GuardedBy;
 import androidx.annotation.NonNull;
 
-import com.google.common.collect.ImmutableSet;
-
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Optional;
-import java.util.stream.Collector;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 final class RunningVdmUidsTracker implements ActivityListener {
@@ -48,7 +47,7 @@ final class RunningVdmUidsTracker implements ActivityListener {
     private final HashMap<Integer, HashSet<Integer>> mDisplayIdToRunningUids = new HashMap<>();
 
     @GuardedBy("mLock")
-    private ImmutableSet<Integer> mRunningVdmUids = ImmutableSet.of();
+    private Set<Integer> mRunningVdmUids = Collections.emptySet();
 
     RunningVdmUidsTracker(@NonNull Context context, @NonNull AudioStreamer audioStreamer) {
         mPackageManager = Objects.requireNonNull(context).getPackageManager();
@@ -64,7 +63,7 @@ final class RunningVdmUidsTracker implements ActivityListener {
             return;
         }
 
-        ImmutableSet<Integer> updatedUids;
+        final Set<Integer> updatedUids;
         synchronized (mLock) {
             HashSet<Integer> displayUidSet =
                     mDisplayIdToRunningUids.computeIfAbsent(displayId, k -> new HashSet<>());
@@ -72,7 +71,7 @@ final class RunningVdmUidsTracker implements ActivityListener {
             mRunningVdmUids =
                     mDisplayIdToRunningUids.values().stream()
                             .flatMap(Collection::stream)
-                            .collect(toImmutableSet());
+                            .collect(Collectors.toSet());
             updatedUids = mRunningVdmUids;
         }
 
@@ -81,15 +80,15 @@ final class RunningVdmUidsTracker implements ActivityListener {
 
     @Override
     public void onDisplayEmpty(int displayId) {
-        ImmutableSet<Integer> uidsBefore;
-        ImmutableSet<Integer> uidsAfter;
+        Set<Integer> uidsBefore;
+        Set<Integer> uidsAfter;
         synchronized (mLock) {
             uidsBefore = mRunningVdmUids;
             mDisplayIdToRunningUids.remove(displayId);
             mRunningVdmUids =
                     mDisplayIdToRunningUids.values().stream()
                             .flatMap(Collection::stream)
-                            .collect(toImmutableSet());
+                            .collect(Collectors.toSet());
             uidsAfter = mRunningVdmUids;
         }
 
@@ -106,8 +105,4 @@ final class RunningVdmUidsTracker implements ActivityListener {
             return Optional.empty();
         }
     }
-
-    private static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {
-        return Collectors.collectingAndThen(Collectors.toList(), ImmutableSet::copyOf);
-    }
 }
diff --git a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/VdmService.java b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/VdmService.java
index 24635b311..deea50957 100644
--- a/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/VdmService.java
+++ b/samples/VirtualDeviceManager/host/src/com/example/android/vdmdemo/host/VdmService.java
@@ -159,7 +159,7 @@ public final class VdmService extends Hilt_VdmService {
                         CHANNEL_ID, "VDM Service Channel", NotificationManager.IMPORTANCE_LOW);
         notificationChannel.enableVibration(false);
         NotificationManager notificationManager = getSystemService(NotificationManager.class);
-        notificationManager.createNotificationChannel(notificationChannel);
+        Objects.requireNonNull(notificationManager).createNotificationChannel(notificationChannel);
 
         Intent openIntent = new Intent(this, MainActivity.class);
         PendingIntent pendingIntentOpen =
@@ -193,7 +193,7 @@ public final class VdmService extends Hilt_VdmService {
         mConnectionManager.addConnectionCallback(mConnectionCallback);
 
         mDisplayManager = getSystemService(DisplayManager.class);
-        mDisplayManager.registerDisplayListener(mDisplayListener, null);
+        Objects.requireNonNull(mDisplayManager).registerDisplayListener(mDisplayListener, null);
 
         mRemoteIo.addMessageConsumer(mRemoteEventConsumer);
 
@@ -241,8 +241,9 @@ public final class VdmService extends Hilt_VdmService {
     }
 
     private void associateAndCreateVirtualDevice() {
-        CompanionDeviceManager cdm = getSystemService(CompanionDeviceManager.class);
-        RoleManager rm = getSystemService(RoleManager.class);
+        CompanionDeviceManager cdm =
+                Objects.requireNonNull(getSystemService(CompanionDeviceManager.class));
+        RoleManager rm = Objects.requireNonNull(getSystemService(RoleManager.class));
         final String deviceProfile =
                 mSettings.deviceStreaming
                         ? AssociationRequest.DEVICE_PROFILE_NEARBY_DEVICE_STREAMING
@@ -255,6 +256,7 @@ public final class VdmService extends Hilt_VdmService {
             if (!rm.isRoleHeld(deviceProfile)) {
                 cdm.disassociate(associationInfo.getId());
             } else if (Objects.equals(associationInfo.getPackageName(), getPackageName())
+                    && associationInfo.getDisplayName() != null
                     && Objects.equals(
                             associationInfo.getDisplayName().toString(),
                             mDeviceCapabilities.getDeviceName())) {
@@ -346,7 +348,8 @@ public final class VdmService extends Hilt_VdmService {
             }
         }
 
-        VirtualDeviceManager vdm = getSystemService(VirtualDeviceManager.class);
+        VirtualDeviceManager vdm =
+                Objects.requireNonNull(getSystemService(VirtualDeviceManager.class));
         mVirtualDevice =
                 vdm.createVirtualDevice(associationInfo.getId(), virtualDeviceBuilder.build());
         if (mRemoteSensorManager != null) {