Passing code as function arguments

Question

I was reading a textbook and I was wondering how come the argument we pass to the function is neither a primitive or an user-defined instance of a class.

SwingU         


        

Answer 1

The code inside SwingUtilities is something like this

private Runnable runnable;

private void invoke(){//called at some point from inside the runnable
     runable.run();
}
public void invokeLater(Runnable runnable){
     this.runnable=runnable;
}

These are called callbacks.