Question

how i can use javadocs to make my application

Answer 1

I am not sure what do you mean but if you want to use documentation in your application which will be transformable to easily readable source (like HTML doc), you will need software called Doxygen which can use specially structured comment blocks (it accepts javadoc style) and transform it to HTML and LaTeX sources. Java, of course, provides this capability itself. You should google for Doxygen's manual and JavaDoc's one.