public static final int STATE_RUNNING = 1000;
  public static final int STATE_JUMPING = 2000;
  public static final int STATE_SHOOTING = 3000;
  switch ( n ) {
    case STATE_RUNNING:
      doRun();
    case STATE_JUMPING:
      doJump();
    case STATE_SHOOTING:
      doShoot();
  }

There's nothing wrong with this, and the int constants are nice and far apart, in case we might want to stick another constant in between RUNNING and JUMPING, like STATE_DUCKING = 2500. But apparently switch statements can be compiled into one of two byte codes, and the faster of the two is used if the ints used are close together, so this would be better:

  public static final int STATE_RUNNING = 1;
  public static final int STATE_JUMPING = 2;
  public static final int STATE_SHOOTING = 3;

Optimierung setzt ja jetzt nicht nur rein auf Prozessorebene an, da gehts auch um Threadhandling, Garbage Collection, Fileaccess, Datentypen usw...

for (f = 0 ; f < 10 ; f++) { machWas(); }

machWas();machWas();machWas();machWas();machWas();machWas();machWas();machWas();machWas();machWas();