java - How Could I add Jcomponent during runtime with Swing Timer -

i have problem making adding randomtext(with random size, font,x,y) jframe every seconds code

first 1 jcomponent expects randomly made string appear

public class randomtextgenerator extends jcomponent{     private string str;     private random r;     private color c;     private font f;     private int x;      private int y;     graphics g;     public randomtextgenerator(string s)     {          r = new random();         c = new color(r.nextint(255),r.nextint(255),r.nextint(255));         f = new font("random",font.bold,r.nextint(100));         x = r.nextint(100);         y = r.nextint(100)+100;         //setpreferredsize(new dimension(500,500));         str = s;     }     public void paintcomponent(graphics g)     {         g.setcolor(c);         g.setfont(f);         system.out.println(str);         g.drawstring(str, x, y);     } } 

another 1 jframe

public class textframe extends jframe{     public textframe() {         this.setsize(500, 500);         this.setdefaultcloseoperation(jframe.exit_on_close);         this.settitle("random text generator");         this.getcontentpane().setbackground(color.black);         this.setlayout(new gridlayout(1,1));         this.add(new randomtextgenerator("aaaaaaaa"));         this.add(new randomtextgenerator("bbbbbbbbbb"));         this.setvisible(true);     }     public void addrandomtext(randomtextgenerator r)     {         this.add(r);         this.add(new randomtextgenerator("ccc"));         system.out.println("method called");         this.repaint();     } } 

above code,

this.add(new randomtextgenerator("aaaaaaaa")); this.add(new randomtextgenerator("bbbbbbbbbb")); 

those ones works , display on screen problem method addrandomtext

this.add(r); this.add(new randomtextgenerator("ccc")); 

those ones not works @ all.

my main method here

public class tfmain {     public static void main(string[] args) {             scanner s = new scanner(system.in);             system.out.println("enter message");             string str = s.nextline();             textframe tf = new textframe();             timer t = new timer(1000,new actionlistener(){                  @override                 public void actionperformed(actionevent arg0) {                     tf.addrandomtext(new randomtextgenerator(str));                 }              });             t.start();         } } 

with code method called appear means timer works.

but why adding jcomponent isn't working?? adding jcomponent in addrandomtext never works(paintcomponent not called too)

please give me advice. sorry bad english