checker/tests/guieffect/UIParent.java

import org.checkerframework.checker.guieffect.qual.SafeEffect;
import org.checkerframework.checker.guieffect.qual.UIType;

@UIType
public class UIParent {
  protected UIElement thingy;

  @SafeEffect // Making this ctor safe to allow easy safe subclasses
  public UIParent() {}

  public void doingUIStuff() {
    thingy.dangerous();
  } // should have UI effect

  @SafeEffect
  public void doingSafeStuff() {} // non-UI
}