Run a simplest test on OS X (I use 10.11):
import java.awt.*;
import java.awt.event.*;

public class MaxiBounds {
    static Frame frame;
    public static void main(String args[]) {
        frame = new Frame("frame");
        frame.setLayout(new GridLayout(2,1));
        frame.setBounds(50,50,200,200);
        frame.setMaximizedBounds(new Rectangle(100,100,350,350));
        frame.setVisible(true);
    }
}

Click Maximize button. The frame would enlarge to 350x350. Click again: it would go back to 200x200. Repeat several times (three or four was enough for me), and eventually the operation would have no effect whatsoever: bounds will be frozen.

I tried this with b120 and b111, both fail like this. The feature was implemented in b68 but I didn't try it that far back.