Class get deleted at run time

[Sandip Hirwale]

Hello All
      I am new to tomcat , i got following error at runtime

java.lang.ClassNotFoundException when I Build my application all the
classes  are present in the web/WEB-INF/classes/ directory

when I run application all the classes get deleted. why this happening?

 i Am usnig tomcat 6.0.20,netbeans6.8, and ubantu system