java - TableModel not called in a JScrollPane containing a JTable -

i having unexpected behavior java gui. want create jscrollpane containing jtable add jscrollpane frame.

here code :

public class urlsscrollpanel extends jscrollpane { private static final long serialversionuid = 1l;  public urlsscrollpanel() {      //setup urls , collections     arraylist<url> urls = url.getall();     arraylist<collection> collections = new arraylist<>();     for(url url : urls) collections.add(new collection(url));      //table     string[] columns = {                     "database",         "status",         "consumption",         "last snapshot date",         "last message",         "details",         "stop collect"     };        abstracttablemodel datamodel = new abstracttablemodel() {         private static final long serialversionuid = 1l;          @override         public object getvalueat(int rowindex, int columnindex) {             system.out.printf("row: %d, column: %d \n", rowindex, columnindex); //is never called.             url url = urls.get(rowindex);             collection collection = collections.get(rowindex);              arraylist<message> lastmessages = collection.getlastsnapshot().getmessages();             message lastmessage = lastmessages.get(lastmessages.size() - 1);              if(columnindex == 0) return url.tostring();             if(columnindex == 1) return collection.getstatus();              if(columnindex == 2) return consumptionchart.getchartpanel(collection);             if(columnindex == 3) return collection.getlastsnapshot().getdate();             if(columnindex == 4) return string.format("[ %s ] %s", lastmessage.getdate(), lastmessage.getbody());              return "comming soon.";         }          @override         public int getrowcount() {             return urls.size();         }          @override         public int getcolumncount() {             return columns.length;         }          @override         public boolean iscelleditable(int row, int column) {             return false;         }     };     jtable table = new jtable(datamodel);     add(table);     setbackground(color.red);     setsize(500, 500); } } 

and here how call :

public static void main(string[] args) {             jframe frame = new jframe();     frame.setvisible(true);     frame.setresizable(true);     frame.setdefaultcloseoperation(jframe.dispose_on_close);     frame.setextendedstate(jframe.maximized_both );     frame.setlocationrelativeto(null);     urlsscrollpanel panel = new urlsscrollpanel();     frame.add(panel, borderlayout.center);     swingutilities.updatecomponenttreeui(frame); } 

the result red square blinking @ top left of frame disappearing immediately. datamodel seems never called.

any in doing wrong appreciated, time!

don't extend jscrollpane. instead, use table construct jscrollpane:

frame.add(new jscrollpane(table), borderlayout.center); 

the approach described here; complete example shown here; alternative approach using setviewportview() examined here.

are these 2 not similar?

jscrollpane panel = new jscrollpane(); panel.add(table); … jscrollpane panel = new jscrollpane(table); 

no. shown in how scroll pane works, first formulation adds table directly jscrollpane, replacing jviewport component occupies central position in scrollpanelayout , have been used display table. second formulation invokes setviewportview(table) internally, tells scroll pane's jviewport component display.