tomcat fail to update newly compiled java files

I am using tomcat 6 web server to do some jsp stuff.

If I made some changes to an associated java file and compile it, tomcat fail to reflect such changes.(if those changes are made to jsp file, it is ok)

However, if I restart the tomcat server, the changes are reflected and everything goes as I exp开发者_运维知识库ect.

I doubt it is the server cache thing. How can I solve it?

For convenience, you can use Tomcat's Manager to Reload An Existing Application.

Addendum: As @Paul comments, Executing Manager Commands With Ant provides a better long-term way to deal with this.