setMaximumSize not working in java

I hava a java program with a JFrame

I am using absolute positioning

here is my main function

public static void main(String[] args) {
    ape Ape = new ape();
    Ape.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Ape.setSize(1000,1000);
    Ape.setMinimumSize(new Dimension(1000,1000));
    Ape.setMaximumSize(new Dimension(1000,1000));
    Ape.setVisible(true);
}

When I run the program I try to resize it and make the window smaller but I can't

when I try to make the window bigger it works fine I basicly skips the setMaximumSize() function

I have read around and aparently this has happened before

is this a known bug?

if so I heard I could make a Window Listener, when I tried it I implemented the functions that WindowListener needed but could not find anything to solve my problem

please try this yourself and see what happens...

thanks in advance

PS... please don't laugh about the names I give my classes... :)