whats wrong with my java code?

public static String aString;
private SensorManager mSensorManager;
private Sensor mAccelerometer;
private ShakeDetector mShakeDetector;

public void onCreate(Bundle savedInstanceState) {
super.onCreate ( savedInstanceState);

    setContentView(R.layout.activity_main); 

    aString = "This variable is set AFTER the 'otherString' variable in Activity";

    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mShakeDetector = new ShakeDetector();
}

public void onPause() {
super.onPause();
unregisterListener(ShakeDetector );
}

public void onResume() {
    super.onResume();
    mSensorManager.registerListener(mShakeDetector, mAccelerometer, SensorManager.SENSOR_DELAY_UI);
}