diff --git a/core/java/android/hardware/camera2/impl/CameraAdvancedExtensionSessionImpl.java b/core/java/android/hardware/camera2/impl/CameraAdvancedExtensionSessionImpl.java
index b52daab284b5e..41370e37f0924 100644
--- a/core/java/android/hardware/camera2/impl/CameraAdvancedExtensionSessionImpl.java
+++ b/core/java/android/hardware/camera2/impl/CameraAdvancedExtensionSessionImpl.java
@@ -98,15 +98,15 @@ public final class CameraAdvancedExtensionSessionImpl extends CameraExtensionSes
 
 
     // Lock to synchronize cross-thread access to device public interface
-    final Object mInterfaceLock = new Object(); // access from this class and Session only!
+    final Object mInterfaceLock;
 
     /**
      * @hide
      */
     @RequiresPermission(android.Manifest.permission.CAMERA)
     public static CameraAdvancedExtensionSessionImpl createCameraAdvancedExtensionSession(
-            @NonNull CameraDevice cameraDevice, @NonNull Context ctx,
-            @NonNull ExtensionSessionConfiguration config, int sessionId)
+            @NonNull android.hardware.camera2.impl.CameraDeviceImpl cameraDevice,
+            @NonNull Context ctx, @NonNull ExtensionSessionConfiguration config, int sessionId)
             throws CameraAccessException, RemoteException {
         long clientId = CameraExtensionCharacteristics.registerClient(ctx);
         if (clientId < 0) {
@@ -183,7 +183,8 @@ public final class CameraAdvancedExtensionSessionImpl extends CameraExtensionSes
     }
 
     private CameraAdvancedExtensionSessionImpl(long extensionClientId,
-            @NonNull IAdvancedExtenderImpl extender, @NonNull CameraDevice cameraDevice,
+            @NonNull IAdvancedExtenderImpl extender,
+            @NonNull android.hardware.camera2.impl.CameraDeviceImpl cameraDevice,
             @Nullable Surface repeatingRequestSurface, @Nullable Surface burstCaptureSurface,
             @NonNull CameraExtensionSession.StateCallback callback, @NonNull Executor executor,
             int sessionId) {
@@ -200,6 +201,7 @@ public final class CameraAdvancedExtensionSessionImpl extends CameraExtensionSes
         mInitialized = false;
         mInitializeHandler = new InitializeSessionHandler();
         mSessionId = sessionId;
+        mInterfaceLock = cameraDevice.mInterfaceLock;
     }
 
     /**
@@ -511,13 +513,14 @@ public final class CameraAdvancedExtensionSessionImpl extends CameraExtensionSes
         public void onConfigured(@NonNull CameraCaptureSession session) {
             synchronized (mInterfaceLock) {
                 mCaptureSession = session;
-                try {
-                    CameraExtensionCharacteristics.initializeSession(mInitializeHandler);
-                } catch (RemoteException e) {
-                    Log.e(TAG, "Failed to initialize session! Extension service does"
-                            + " not respond!");
-                    notifyConfigurationFailure();
-                }
+            }
+
+            try {
+                CameraExtensionCharacteristics.initializeSession(mInitializeHandler);
+            } catch (RemoteException e) {
+                Log.e(TAG, "Failed to initialize session! Extension service does"
+                        + " not respond!");
+                notifyConfigurationFailure();
             }
         }
     }
@@ -525,46 +528,56 @@ public final class CameraAdvancedExtensionSessionImpl extends CameraExtensionSes
     private class InitializeSessionHandler extends IInitializeSessionCallback.Stub {
         @Override
         public void onSuccess() {
-            boolean status = true;
-            synchronized (mInterfaceLock) {
-                try {
-                    if (mSessionProcessor != null) {
-                        mSessionProcessor.onCaptureSessionStart(mRequestProcessor);
-                        mInitialized = true;
-                    } else {
-                        Log.v(TAG, "Failed to start capture session, session released before " +
-                                "extension start!");
-                        status = false;
-                        mCaptureSession.close();
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    boolean status = true;
+                    synchronized (mInterfaceLock) {
+                        try {
+                            if (mSessionProcessor != null) {
+                                mSessionProcessor.onCaptureSessionStart(mRequestProcessor);
+                                mInitialized = true;
+                            } else {
+                                Log.v(TAG, "Failed to start capture session, session " +
+                                                " released before extension start!");
+                                status = false;
+                            }
+                        } catch (RemoteException e) {
+                            Log.e(TAG, "Failed to start capture session,"
+                                    + " extension service does not respond!");
+                            status = false;
+                            mInitialized = false;
+                        }
                     }
-                } catch (RemoteException e) {
-                    Log.e(TAG, "Failed to start capture session,"
-                            + " extension service does not respond!");
-                    status = false;
-                    mCaptureSession.close();
-                }
-            }
 
-            if (status) {
-                final long ident = Binder.clearCallingIdentity();
-                try {
-                    mExecutor.execute(
-                            () -> mCallbacks.onConfigured(CameraAdvancedExtensionSessionImpl.this));
-                } finally {
-                    Binder.restoreCallingIdentity(ident);
+                    if (status) {
+                        final long ident = Binder.clearCallingIdentity();
+                        try {
+                            mExecutor.execute(() -> mCallbacks.onConfigured(
+                                    CameraAdvancedExtensionSessionImpl.this));
+                        } finally {
+                            Binder.restoreCallingIdentity(ident);
+                        }
+                    } else {
+                        onFailure();
+                    }
                 }
-            } else {
-                notifyConfigurationFailure();
-            }
+            });
         }
 
         @Override
         public void onFailure() {
-            mCaptureSession.close();
-            Log.e(TAG, "Failed to initialize proxy service session!"
-                    + " This can happen when trying to configure multiple "
-                    + "concurrent extension sessions!");
-            notifyConfigurationFailure();
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    mCaptureSession.close();
+
+                    Log.e(TAG, "Failed to initialize proxy service session!"
+                            + " This can happen when trying to configure multiple "
+                            + "concurrent extension sessions!");
+                    notifyConfigurationFailure();
+                }
+            });
         }
     }
 
diff --git a/core/java/android/hardware/camera2/impl/CameraExtensionSessionImpl.java b/core/java/android/hardware/camera2/impl/CameraExtensionSessionImpl.java
index 41822e77f9536..6bca732feca52 100644
--- a/core/java/android/hardware/camera2/impl/CameraExtensionSessionImpl.java
+++ b/core/java/android/hardware/camera2/impl/CameraExtensionSessionImpl.java
@@ -114,7 +114,7 @@ public final class CameraExtensionSessionImpl extends CameraExtensionSession {
     private boolean mInternalRepeatingRequestEnabled = true;
 
     // Lock to synchronize cross-thread access to device public interface
-    final Object mInterfaceLock = new Object(); // access from this class and Session only!
+    final Object mInterfaceLock;
 
     private static int nativeGetSurfaceFormat(Surface surface) {
         return SurfaceUtils.getSurfaceFormat(surface);
@@ -125,7 +125,7 @@ public final class CameraExtensionSessionImpl extends CameraExtensionSession {
      */
     @RequiresPermission(android.Manifest.permission.CAMERA)
     public static CameraExtensionSessionImpl createCameraExtensionSession(
-            @NonNull CameraDevice cameraDevice,
+            @NonNull android.hardware.camera2.impl.CameraDeviceImpl cameraDevice,
             @NonNull Context ctx,
             @NonNull ExtensionSessionConfiguration config,
             int sessionId)
@@ -223,7 +223,7 @@ public final class CameraExtensionSessionImpl extends CameraExtensionSession {
             @NonNull IPreviewExtenderImpl previewExtender,
             @NonNull List<Size> previewSizes,
             long extensionClientId,
-            @NonNull CameraDevice cameraDevice,
+            @NonNull android.hardware.camera2.impl.CameraDeviceImpl cameraDevice,
             @Nullable Surface repeatingRequestSurface,
             @Nullable Surface burstCaptureSurface,
             @NonNull StateCallback callback,
@@ -249,6 +249,7 @@ public final class CameraExtensionSessionImpl extends CameraExtensionSession {
         mSupportedRequestKeys = requestKeys;
         mSupportedResultKeys = resultKeys;
         mCaptureResultsSupported = !resultKeys.isEmpty();
+        mInterfaceLock = cameraDevice.mInterfaceLock;
     }
 
     private void initializeRepeatingRequestPipeline() throws RemoteException {
@@ -856,46 +857,56 @@ public final class CameraExtensionSessionImpl extends CameraExtensionSession {
     private class InitializeSessionHandler extends IInitializeSessionCallback.Stub {
         @Override
         public void onSuccess() {
-            boolean status = true;
-            ArrayList<CaptureStageImpl> initialRequestList =
-                    compileInitialRequestList();
-            if (!initialRequestList.isEmpty()) {
-                try {
-                    setInitialCaptureRequest(initialRequestList,
-                            new InitialRequestHandler(
-                                    mRepeatingRequestImageCallback));
-                } catch (CameraAccessException e) {
-                    Log.e(TAG,
-                            "Failed to initialize the initial capture "
-                                    + "request!");
-                    status = false;
-                }
-            } else {
-                try {
-                    setRepeatingRequest(mPreviewExtender.getCaptureStage(),
-                            new PreviewRequestHandler(null, null, null,
-                                    mRepeatingRequestImageCallback));
-                } catch (CameraAccessException | RemoteException e) {
-                    Log.e(TAG,
-                            "Failed to initialize internal repeating "
-                                    + "request!");
-                    status = false;
-                }
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    boolean status = true;
+                    ArrayList<CaptureStageImpl> initialRequestList =
+                            compileInitialRequestList();
+                    if (!initialRequestList.isEmpty()) {
+                        try {
+                            setInitialCaptureRequest(initialRequestList,
+                                    new InitialRequestHandler(
+                                            mRepeatingRequestImageCallback));
+                        } catch (CameraAccessException e) {
+                            Log.e(TAG,
+                                    "Failed to initialize the initial capture "
+                                            + "request!");
+                            status = false;
+                        }
+                    } else {
+                        try {
+                            setRepeatingRequest(mPreviewExtender.getCaptureStage(),
+                                    new PreviewRequestHandler(null, null, null,
+                                            mRepeatingRequestImageCallback));
+                        } catch (CameraAccessException | RemoteException e) {
+                            Log.e(TAG,
+                                    "Failed to initialize internal repeating "
+                                            + "request!");
+                            status = false;
+                        }
 
-            }
+                    }
 
-            if (!status) {
-                notifyConfigurationFailure();
-            }
+                    if (!status) {
+                        notifyConfigurationFailure();
+                    }
+                }
+            });
         }
 
         @Override
         public void onFailure() {
-            mCaptureSession.close();
-            Log.e(TAG, "Failed to initialize proxy service session!"
-                    + " This can happen when trying to configure multiple "
-                    + "concurrent extension sessions!");
-            notifyConfigurationFailure();
+            mHandler.post(new Runnable() {
+                @Override
+                public void run() {
+                    mCaptureSession.close();
+                    Log.e(TAG, "Failed to initialize proxy service session!"
+                            + " This can happen when trying to configure multiple "
+                            + "concurrent extension sessions!");
+                    notifyConfigurationFailure();
+                }
+            });
         }
     }