java - Smooth components automatic refresh after modifications or loops (ex: timer) -

i've looked many place , can't find out how refresh automatically frame. work (since i've used many examples there) when click buttons, not automatically.

i want create minesweeper game, , adding timer in it, works except timer counts, updates when button clicked. therefore, redoing layout won't work...

tough know timer works, if put system.out in it, see @ stable second rate.

i put below little program, not game since code long, little 1 built same circumstances, fixing fix problem overall.

in case, don't have developed button other program, time refresh when i'm messing window.

import java.awt.borderlayout; import java.awt.component; import java.awt.gridlayout; import java.util.timer; import java.util.timertask; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.jtextfield;  public class clocktest { jframe frame = new jframe(); jbutton test1 = new jbutton(); jtextfield timer1 = new jtextfield(); int hour = 0, min = 0, sec = 0; string timing;  public clocktest() {     frame.setlayout(new borderlayout());     frame.setdefaultcloseoperation(jframe.exit_on_close);     frame.add(center(), borderlayout.center);     frame.pack();     frame.setvisible(true); }  public component center() {     jpanel pan = new jpanel();     pan.setlayout(new gridlayout(1,2));     test1.settext("dummy");     timer1.seteditable(false);     timer1.settext(timing);     pan.add(test1);     pan.add(timer1);     return pan; }  public void count() {     sec++;     if(sec == 60) {         sec -= 60;         min++;     }     if(min == 60) {         min -= 60;         hour++;     }     timing = hour + ":" + min + " : " + sec; //this in game refresh, set flags, mine "exploded"... //but since i'm not pressing anything... not happen.     frame.add(center(), borderlayout.center); }  public static void main(string[]args) {     final   clocktest test1 = new clocktest();     timertask task = new timertask() {         public void run() {             test1.count();         }     };     timer t = new timer();     t.schedule(task,0,1000); } } 

jpanel in puzzle game not updating

after changing components, need 'refresh' swing component calling invalidate() or revalidate()