java - No Main Function -

ok, trying run , tells me there no main (i have tried putting 1 in , termination , syntax error) wrong and/or put main function?

here code

import javax.swing.*;  import java.awt.*; import java.awt.event.*;  public class stylelistener extends jpanel { private static final long serialversionuid = 1l; private jcheckbox bold, italic; private jlabel saying; private jsplitpane splitpane;  public stylelistener()   {      splitpane = new jsplitpane(jsplitpane.vertical_split);    splitpane.setonetouchexpandable(true);    splitpane.setpreferredsize(new dimension(300,200));    splitpane.setbackground(color.green);    splitpane.setdividerlocation(100);     jpanel subpanel1 = new jpanel();    subpanel1.setpreferredsize(new dimension(300, 100));    subpanel1.setbackground(color.cyan);    saying = new jlabel ("say style!");    saying.setfont (new font ("helvetica", font.plain, 36));    subpanel1.add (saying);    splitpane.settopcomponent(subpanel1);     jpanel subpanel2 = new jpanel();    subpanel2.setpreferredsize(new dimension(300, 100));    subpanel2.setbackground(color.green);    bold = new jcheckbox ("bold");    bold.settooltiptext("check box make text fatter.");    bold.setbackground (color.green);    italic = new jcheckbox ("italic");    italic.settooltiptext("check box make text slantier looking.");    italic.setbackground (color.green);    subpanel2.add (bold);    subpanel2.add (italic);    splitpane.setbottomcomponent(subpanel2);     add(splitpane);     stylelistener listener = new stylelistener();    bold.additemlistener (listener);    italic.additemlistener (listener);     public void itemstatechanged (itemevent event)    {       int style = font.plain;        if (bold.isselected())         style = font.bold;        if (italic.isselected())         style += font.italic;        saying.setfont (new font ("helvetica", style, 36));    } 

it's class file.. before trying copy classes should make sure have main function..

try hello world project , add class file project..