java - initializing more than one JFrame creates blank JFrames -

i'm new swing , i'm having trouble replacing existing jframe. initialize first jframe without problem...

main:

public static jframe jf; public static int state = 0;  public static void main(string args[]) {     jf = new mainmenu();     jf.setvisible(true);     while (state != -1) {}   } 

mainmenu:

public mainmenu() {     settitle("battleship");     setdefaultcloseoperation(jframe.exit_on_close);     setbounds(100, 100, 450, 300);     contentpane = new jpanel();     contentpane.setborder(new emptyborder(5, 5, 5, 5));     setcontentpane(contentpane);      jbutton btnsingleplayer = new jbutton("single player - easy");     btnsingleplayer.addmouselistener(new mouseadapter() {         @override         public void mouseclicked(mouseevent arg0) {             gamedriver gd = new gamedriver(1);         }     });      jbutton btnsplitscreenmultiplayer = new jbutton("split screen multiplayer");     btnsplitscreenmultiplayer.addmouselistener(new mouseadapter() {         @override         public void mouseclicked(mouseevent arg0) {             gamedriver gd = new gamedriver(0);         }     });      jbutton btnonlinemultiplayer = new jbutton("online multiplayer");     btnonlinemultiplayer.setenabled(false);      jbutton btnhowtoplay = new jbutton("how play");     btnhowtoplay.addmouselistener(new mouseadapter() {         @override         public void mouseclicked(mouseevent e) {             if (desktop.isdesktopsupported()) {                 try {                      //set page url in string. eg, m using url google search engine                      string url = "http://www.hasbro.com/common/instruct/battleship.pdf";                      java.awt.desktop.getdesktop().browse(java.net.uri.create(url));                    }                    catch (java.io.ioexception e2) {                        system.out.println(e2.getmessage());                    }             }         }     });     grouplayout gl_contentpane = new grouplayout(contentpane);     gl_contentpane.sethorizontalgroup(         gl_contentpane.createparallelgroup(alignment.leading)             .addgroup(alignment.trailing, gl_contentpane.createsequentialgroup()                 .addcontainergap(128, short.max_value)                 .addgroup(gl_contentpane.createparallelgroup(alignment.trailing, false)                     .addcomponent(btnhowtoplay, alignment.leading, grouplayout.default_size, grouplayout.default_size, short.max_value)                     .addcomponent(btnonlinemultiplayer, alignment.leading, grouplayout.default_size, grouplayout.default_size, short.max_value)                     .addcomponent(btnsingleplayer, alignment.leading, grouplayout.default_size, grouplayout.default_size, short.max_value)                     .addcomponent(btnsplitscreenmultiplayer, alignment.leading))                 .addgap(121))     );     gl_contentpane.setverticalgroup(         gl_contentpane.createparallelgroup(alignment.leading)             .addgroup(alignment.trailing, gl_contentpane.createsequentialgroup()                 .addcontainergap(89, short.max_value)                 .addcomponent(btnsingleplayer)                 .addpreferredgap(componentplacement.related)                 .addcomponent(btnsplitscreenmultiplayer)                 .addpreferredgap(componentplacement.related)                 .addcomponent(btnonlinemultiplayer)                 .addpreferredgap(componentplacement.related)                 .addcomponent(btnhowtoplay)                 .addgap(45))     );     contentpane.setlayout(gl_contentpane); } 

but once enter gamedriver , try initialize different jframe...

gamedriver:

//stuff happens programshell.jf.setvisible(false); programshell.jf = new placementwindow(currentplayer, otherplayer, curship); programshell.jf.setvisible(true); 

i blank jframe without of it's components (it created when use placementwindow's main initialize)

placementwindow:

private jpanel contentpane; private gameboard gbcur; private gameboard gboth; private int curplacement; private string title; private int sqsize = 21; private int xoffset = 27; private int yoffset = 27; private int divoffset = 283;  public placementwindow(gameboard cur, gameboard oth, int curship) {     this.gbcur = cur;     this.gboth = oth;     this.curplacement = curship;     title = "battleship! " + cur.getname() + ", place ships";      settitle(title);     setbounds(100, 100, 518, 389);     setdefaultcloseoperation(jframe.exit_on_close);      contentpane = new jpanel();     contentpane.setborder(new emptyborder(5, 5, 5, 5));     setcontentpane(contentpane);      //stuff added content pane      imagepanel leftboard = new imagepanel("graphicsassets/boardgraphic.png");     leftboard.setbounds(6, 6, 250, 250);     getcontentpane().add(leftboard);              //more stuff added content pane      contentpane.setlayout(null); } 

i recognize approach little unconventional, i'm trying work within limitations of code not designed swing (and must remain, part, intact). appreciated!

edit

i've modified code mimic vince's along following function:

public static void update(/*new values*/) {    frame.remove(pp);    secondpanel = new secondpanel(/*new values*/);    frame.add(pp, "secondpanel");    switchpanel("secondpanel"); 

unfortunately frame doesn't switch original mainmenu frame upon calling update. ideas?

don't initialize new frames. if want switch 1 panel another, set frame's layout cardlayout, , add jpanels.

class myframe {      static cardlayout cl = new cardlayout(); //handles panel switching      static jframe frame; //init swing on edt     static firstpanel firstpanel;     static secondpanel secondpanel;      public static void main(string[] args) {          initframe();     }      public static void initframe() {          swingutilities.invokelater(new runnable() {               public void run() {                    frame = new jframe();                    frame.setdefaultcloseoperation(3);                    frame.setlayout(cl);                     firstpanel = new firstpanel();                    secondpanel = new secondpanel();                      //first panel added frame show first                    frame.add(firstpanel, "first");                    frame.add(secondpanel, "second");                    frame.pack(); //sizes frame fit panel being shown                     setvisible(true);               }          });     }      public static void switchpanel(string name) {          cl.show(frame.getcontentpane(), name);          frame.pack();     } }     class firstpanel extends jpanel { } class secondpanel extends jpanel { } 

you use panels if needed, can switch/dispose/create panels instead of entire frame.

but, games, don't use panel approach. games use 1 panel, , instead. if doesn't make sense you, answered question simple game design: jframe, jpanel, keylistener questions

i suggest looking game states. big deal when comes games. allows render/update depending on state game @ (menu, game, pause, ect..)