java - How to make jinternal frame ceter in main frame? -

i working on java project. i've created main frame desktop pane , several j internal frames. want center j internal frames. can give me suggestion how center ? thanks.

try logic. i'd done 1 jinternalframe.

import javax.swing.jframe; import javax.swing.jinternalframe; import javax.swing.jdesktoppane; import javax.swing.swingutilities; import java.awt.event.componentadapter; import java.awt.event.componentevent; import java.awt.component;  public final class centerchild extends jframe{      private jdesktoppane   contentpane;     private jinternalframe child;      @override     public void frameinit(){         super.frameinit();         setvisible(true);         setdefaultcloseoperation(jframe.exit_on_close);         setbounds(0,0,500,500);         this.selfinitialize();     }      private void selfinitialize(){         contentpane = new jdesktoppane();         child       = new jinternalframe("centered child");          child.setclosable(true);         child.setvisible(true);          child.setsize(300,200);         //centering jinternalframe         child.setlocation((getwidth() - child.getwidth())/2, (getheight() - child.getheight())/2);          contentpane.add(child);         this.setcontentpane(contentpane);          addcomponentlistener(new resizeeventhandler());     }     public static void main(string[] args) {         swingutilities.invokelater(()->{ new centerchild();});     }     //code re positions jinternalframe while main window size changes     private class resizeeventhandler extends componentadapter{         @override         public void componentresized(componentevent e){             component invoker = e.getcomponent();             //re positioning jinternalframe main window's center             child.reshape((invoker.getwidth() - child.getwidth())/2, (invoker.getheight() - child.getheight())/2,300,200);                   }     } }