I have a project in java named java.war.
where war means web archive files. i dont know where to place this project in tomcat directory or netbean IDE.
can any one tell me?

In NetBeans IDE there is a directory called "dist". You can place your web files in that directory. The path is like this :
"/yournetbeanshomedirectory/yourproject/dist/yourwar.war".

thanks.
but i can't resolve my problem. i repeat.
i download a project from internet for modification.
it is in .war form.
now this projct is in my Document.
i want to know where should i place it in tomcat or netbean IDE.
i never find any DIST directory.
and how to deploy that project?

If you put it in Tomcat's webapps directory and then start Tomcat [either as a service or by double clicking the tomcat file in /bin] it will unpack the .war.

edit: Just read stul's link, which said basically the same thing. Sorry I wasted my time.