java - GUI thread updating issue -

i have gui class gui:

public class gui extends jframe implements runnable {  private jpanel outer, inner; private jlabel[][] labels = new jlabel[22][12]; private color[][] defaultmap, map; thread t; private int row, col; private color color;  public gui() {     container content = getcontentpane();     content.setlayout(new borderlayout());      setbackground(color.black);     setsize(1000, 1000);     setlocation(300, 0);     setdefaultcloseoperation(jframe.exit_on_close);     setresizable(false);      defaultmap = createmap();     draw(defaultmap); }  public color[][] createmap() {     color[][] map = new color[22][12];     (int = 0; < 22; i++)     {         (int j = 0; j < 12; j++)         {             map[i][j] = color.white;         }     }     (int = 0; < 22; i++)     {         map[i][0] = color.gray;         map[i][11] = color.gray;     }     (int = 0; < 12; i++)     {         map[0][i] = color.gray;         map[21][i] = color.gray;     }     return map; }  public void draw(color[][] map) {      outer = new jpanel();     outer.setlayout(new borderlayout());     outer.setbackground(color.white);     outer.setpreferredsize(new dimension());      inner = new jpanel();     inner.setlayout(new gridlayout(22, 12, 2, 2));     inner.setbackground(color.black);      (int = 0; < 22; i++)     {         (int j = 0; j < 12; j++)         {             labels[i][j] = new jlabel();             jlabel label = labels[i][j];             label.setpreferredsize(new dimension(20, 20));             label.setbackground(map[i][j]);             label.setopaque(true);             inner.add(label);         }     }      add(outer);     add(inner);     pack(); }  public void move(int row, int col, color color) {     system.out.println(row+","+col);     map = defaultmap;     map[row][col] = color;     t = new thread(this);     t.start(); }  @override public void run() {     draw(map); } } 

which called main class so:

public static void main(string[] args) {     swingutilities.invokelater(new runnable()     {         @override         public void run()         {             try             {                 gui = new gui();                 gui.setvisible(true);                 gui.move(2,5,color.green);                 thread.sleep(1000);                 gui.move(3,5,color.green);                 thread.sleep(1000);                 gui.move(4,5,color.green);             } catch (interruptedexception ex)             {                 logger.getlogger(tetris.class.getname()).log(level.severe, null, ex);             }         }     }); } 

so weird stuff happening when gui.move() function called. can ignore rest or use if helps. each time, green block should "added" gui @ 2,5; 3,5; , 4,5; 1 second after other.

the issue:

the gui remains black time repaints/updates proper grid , colors first 2 blocks correctly colored green it's missing last block @ 4,5. again, initial "defaultmap" should painted immediately, not, jframe black until painted @ once minus last green block. each green block should painted on 1 second after other.

the interesting part system.out.println() bit in move method in gui prints out row , col i'd expect to... come out 1 second after other in terminal. tells me going right. i'm not sure what's going on gui...

edit: slight difference in story. upon closer examination, noticed last green block appear second entire map painted "disappears" repainted white.

you sleeping on edt (event dispatching thread). should never block edt.

• never call sleep or wait on edt
• move long running tasks other threads (using executors or swingworker)
• for repeated or delayed update of ui, can use javax.swing.timer
• all ui-operations should performed on edt (using swingutilities.invokelater or javax.swing.timer or swingworker

read more swing concurrency in swing tag wiki.