class MinFrame {
private final static int minWidth=200;
private final static int minHeigth=200;
public static void main(String[] args) {
final JFrame frame=new JFrame();
frame.setSize(300,300);
frame.show();
frame.addWindowListener(new WindowAdapter(){
public void windowStateChanged(WindowEvent e) {
System.out.println("change");
if (frame.getWidth()<minWidth){
frame.setSize(minWidth,frame.getHeight());
}
if (frame.getHeight()<minHeigth){
frame.setSize(frame.getWidth(),minHeigth);
}