How to disable BACK button in Android app

To override the back button in an Android application,
override the Activity method onBackPressed() to return

public class MyActivity extends Activity {

@Override
public void onBackPressed() {
return;
}
}

EDIT: 

Chintan commented that this snippet is also a solution:

@Override
public boolean onKeyDown(int keyCode,KeyEvent event) {
 if ((keyCode == KeyEvent.KEYCODE_BACK

    || KeyEvent.KEYCODE_HOME == keyCode

    || KeyEvent.KEYCODE_SEARCH == keyCode)){
  return false;
 }
 return super.onKeyDown(keyCode, event);