The Foundation of Game Play Loop: The JavaFX Pulse System and the Game Processing Architecture - Beginning Java 8 Games Development - page 229

Figure 7-6 . Once you extend and import AnimationTimer, NetBeans throws an error: class does not implement the
.handle()
As you can see at the bottom left of the error message pop-up, you can use the
Alt+Enter keystroke combination to bring up a helper dialog, which will offer you
several solutions, including one that will actually write the unimplemented .handle()
method for you. Select Implement all abstract methods , shown in Figure 7-7 , high-
lighted in blue. Once you double-click this option, NetBeans will write this method
structure for you:
@Override
public void handle (long now ) {
throw new UnsupportedOperationException("Not
supported yet.");
}