if (next != null)
  public void focusNextComponent (Component comp)  {    Component focusComp = (comp == null) ? getGlobalFocusOwner () : comp;    Container focusCycleRoot = focusComp.getFocusCycleRootAncestor ();    FocusTraversalPolicy policy = focusCycleRoot.getFocusTraversalPolicy ();    Component next = policy.getComponentAfter (focusCycleRoot, focusComp);    next.requestFocusInWindow ();  }