I have developed a program applet and frame in it the program is perfect but i dont how to know run it in command prompt

Compile your java source, and you will get a *.class file after successful compilation.

e.g, A.class

Then create a html file e.g, RunApplet.html and write the following code in it

<html>
<head> </head>
<body>
  <applet code = "A.class"
          width = "400"
          height = "400" >    
  </applet>
</body>
</html>

Now in cmd prompt run ::

appletviewer RunApplet.html