java - JFrame doesn't conform JPanel's setMinimunSize() -

i expect jpanel's setminimumsize() confine resizing of jframe too, doesn't.

the following example code:

import java.awt.borderlayout; import java.awt.color; import java.awt.dimension; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.jsplitpane;  public class autoresize{      public static void main(string[] args) {          jpanel leftpanel = new jpanel();         jpanel rightpanel = new jpanel();         leftpanel.setbackground(color.red);         rightpanel.setbackground(color.blue);         leftpanel.setsize(500,400);         rightpanel.setsize(500,400);         dimension d = new dimension(450,300);         leftpanel.setminimumsize(d);         rightpanel.setminimumsize(d);          jsplitpane split;         split = new jsplitpane(jsplitpane.horizontal_split, leftpanel, rightpanel);         split.setdividerlocation(400);          jframe frame = new jframe();         frame.getcontentpane().setlayout(new borderlayout());         frame.getcontentpane().add(split, borderlayout.center);         frame.setsize(1000, 800);         frame.setdefaultcloseoperation(jframe.exit_on_close);         frame.setvisible(true);     } } 

if resize jframe small size produces this:

what want jframe couldn't resized smaller region jpanels' minimum size. there anyway implement this?

all need adding frame.setminimumsize(); , feel dumb.

thanks @andrew thompson @madprogrammer , @user1803551

import java.awt.borderlayout; import java.awt.color; import java.awt.dimension; import java.awt.toolkit; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.jsplitpane;  public class autoresize{      private final dimension screensize = toolkit.getdefaulttoolkit().getscreensize();     private final double w = screensize.getwidth();     private final double h = screensize.getheight();     private final dimension d = new dimension((int) w/3,(int) h/3);      public void run() {         jpanel leftpanel = new jpanel();         jpanel rightpanel = new jpanel();         leftpanel.setbackground(color.red);         rightpanel.setbackground(color.blue);         //leftpanel.setsize(500,400);         //rightpanel.setsize(500,400);         leftpanel.setminimumsize(d);         rightpanel.setminimumsize(d);          jsplitpane split;         split = new jsplitpane(jsplitpane.horizontal_split, leftpanel, rightpanel);         split.setdividerlocation(400);          jframe frame = new jframe();         frame.getcontentpane().setlayout(new borderlayout());         frame.getcontentpane().add(split, borderlayout.center);          frame.setsize((int) w,(int) h);         //frame.pack();         frame.setminimumsize(new dimension((int) w/3*2,(int) h/3*2));         frame.setdefaultcloseoperation(jframe.exit_on_close);         frame.setvisible(true);     }      public static void main(string[] args) {         autoresize test = new autoresize();         test.run();     } }