小编Оле*_*ков的帖子

当我看到它有效时，我感到非常惊讶。请解释原因

https://github.com/bethrobson/Head-First-Java/blob/master/chap12/MiniMusicPlayer3.java

public void setUpGui() {  //  <------- it is not static
    ml = new MyDrawPanel();
    f.setContentPane(ml);
    f.setBounds(30, 30, 300, 300);
    f.setVisible(true);
}

public void go() {    
    setUpGui();  //  <---  call without object.setUpGui() !!! 

为什么它有效？