Fail to connect camera service in front camera?-Collection of common programming errors

i am using Camera Api in that when ever i lanch app it will show back camera it works fine but when i click front camera button it will get Runtime excetion Fail to connect camera service

in  camera = Camera.open(cameraID);

in front camera button code :

if (cameraID == Camera.CameraInfo.CAMERA_FACING_BACK)
            {
                Toast.makeText(getApplicationContext(), "Front Camera", Toast.LENGTH_LONG).show();

                cameraID = Camera.CameraInfo.CAMERA_FACING_FRONT;

            }
            else if (cameraID == Camera.CameraInfo.CAMERA_FACING_FRONT)

            {
                Toast.makeText(getApplicationContext(), "Back Camera", Toast.LENGTH_LONG).show();

                cameraID = Camera.CameraInfo.CAMERA_FACING_BACK;

            }

            Intent intent = getIntent();

            finish();

            startActivity(intent);