java - How to a new element to JFrame and have it show -

i have gui scroll pane in it. scroll pane scrolling though jpanel of jpanels. ability add 1 more list of subjpanels , have jframe update it.

right have array updating, not jframe.

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package sscce;  import java.awt.borderlayout; import java.awt.dimension; import java.awt.flowlayout; import java.awt.gridlayout; import java.awt.toolkit; import java.awt.event.actionevent; import java.awt.event.actionlistener; import java.io.ioexception; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.jscrollpane; import javax.swing.jtextfield;  public class add extends jframe{     private jpanel[] branches;     private jpanel pane; //pane stores accounts     private jscrollpane scroller;     private jbutton newbranch;      public static void main(string[] args) {         jframe frame = new add();     }      public add(){         this.setdefaultcloseoperation(jframe.exit_on_close);         this.setsize(500, 500);         this.settitle("how add?");          this.setlayout(new borderlayout());          this.add(statusbar(), borderlayout.north);          populatebranches();          pane = new jpanel();         pane.setlayout(new gridlayout(branches.length,1));         (int = 0; < branches.length; i++){             pane.add(branches[i]);         }          scroller = new jscrollpane(pane);         scroller.createverticalscrollbar();         this.add(scroller,borderlayout.center);          this.setvisible(true);     }      private jpanel statusbar(){         jpanel statusbar = new jpanel();         statusbar.setlayout(new flowlayout());          newbranch = new jbutton("new branch");                 newbranch.addactionlistener(new buttoneventhandler());          statusbar.add(newbranch);         return statusbar;     }      private void populatebranches(){         branches = new jpanel[2];          (int = 0; < branches.length; i++){             branches[i] = new jpanel();             branches[i].setlayout(new flowlayout());             branches[i].add(new jtextfield(20));         }     }      private void newbranch(){         jpanel[] tempbranches = new jpanel[branches.length + 1];                 system.out.println(tempbranches.length);          (int = 0; < branches.length; i++){             tempbranches[i] = branches[i];         }          tempbranches[branches.length] = new jpanel();         tempbranches[branches.length].setlayout(new flowlayout());         tempbranches[branches.length].add(new jtextfield(20));         branches = tempbranches;          pane = new jpanel();         pane.setlayout(new gridlayout(branches.length, 1));         (int = 0; < branches.length; i++){             pane.add(branches[i]);         }                 pane.repaint();                 pane.validate();          scroller = new jscrollpane(pane);         this.add(scroller, borderlayout.center);          this.repaint();         this.validate();     }      private class buttoneventhandler implements actionlistener {         @override         public void actionperformed(actionevent event) {             string btnclkd = event.getactioncommand();             if (btnclkd.equals("new branch")){                 newbranch();             }          }     } } 

if allow gridlayout grow, can add more components it:

// 0 means new rows added needed pane.setlayout(new gridlayout(0, 1));  // ...  private void newbranch(){     // create component     jpanel branch = new jpanel();     branch.add(new jtextfield(20));     // + additional subcomponents      // , add others     pane.add(branch);     pane.revalidate(); }