Fatal Exception: java.lang.IllegalArgumentException: Receiver not registered: android.hardware.camera2.CameraManager

I am developing a flashlight app that switch on/off the system tourch.

I have a crash that shown on Android M (v6.0) on

Crashlytics

Here is the Issue details and stacktrace:

Fatal Exception: java.lang.IllegalArgumentException: Receiver not registered: android.hardware.camera2.CameraManager$1@49e5f1b
   at android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:789)
   at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:1222)
   at android.hardware.camera2.CameraManager$3.run(CameraManager.java:1266)
   at android.os.Handler.handleCallback(Handler.java:815)
   at android.os.Handler.dispatchMessage(Handler.java:104)
   at android.os.Looper.loop(Looper.java:207)
   at android.app.ActivityThread.main(ActivityThread.java:5728)
   at java.lang.reflect.Method.invoke(Method.java)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

I have the following Manifest permissions and hardware features:

<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.flash" />

and

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.FLASHLIGHT" />

****EDIT:****

Here is the code I am using to access the camera:

// Here, I am checking if SDK >= M
if (VersionUtils.isMarshmallowOrGreater()) {

        cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);

        if (cameraManager != null) {

            try {
                cameraId = cameraManager.getCameraIdList()[0];
            } catch (CameraAccessException | ArrayIndexOutOfBoundsException e) {
                e.printStackTrace();
            }
        }

} else {

        if (camera == null || camera.getParameters() == null) {

            try {
                camera = Camera.open();
                params = camera.getParameters();
            } catch (RuntimeException e) {
                e.printStackTrace();
            }
        }

}

Here is the code to switch on the flash/tourch:

if (VersionUtils.isMarshmallowOrGreater()) {

            try {
                cameraManager.setTorchMode(cameraId, true);
            } catch (Exception e) {
                e.printStackTrace();
            }

 } else {

            if (camera == null || params == null || camera.getParameters() == null) {
                getCamera();
                return;
            }

            params = camera.getParameters();
            params.setFlashMode(Parameters.FLASH_MODE_TORCH);
            camera.setParameters(params);

            startCameraPreview();

 }

Also, here is the code of switching off the camera flash:

if (VersionUtils.isMarshmallowOrGreater()) {

            try {
                cameraManager.setTorchMode(cameraId, false);
            } catch (Exception e) {
                e.printStackTrace();
            }

 } else {

            if (camera == null || params == null || camera.getParameters() == null) {
                return;
            }

            try {

                params = camera.getParameters();
                params.setFlashMode(Parameters.FLASH_MODE_OFF);
                camera.setParameters(params);
                stopCameraPreview();
                camera.release();
                camera = null;

            } catch (Exception e) {
                e.printStackTrace();
            }
 }

Code of startCameraPreview() method:

private void startCameraPreview() {
    try {
        camera.startPreview();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

I don't have any receiver in my app except the widget provider class but I don't have any line of code the do (register/unregister) a receiver!!

I searched and read many links resources regarding this issue but I could not find any clue to exactly know the line which causing it.

Anyone faced this issue, your help is appreciated.

from Fatal Exception: java.lang.IllegalArgumentException: Receiver not registered: android.hardware.camera2.CameraManager