RPM Packaging doubts

[ram s]

Hello,
I am trying to create one RPM package for my java application.

Already ant files and source file are there.

I need to create final package that install my application in to a
specific directory and run the ant to create classes.

What is the procedure for creating RPM package for java application.

2) Also, in spec file , we are putting RPM_BUILD_ROOT macro.

But, where it is defined.

shall we define it as my rpm build directory.

RPM_BUILD_ROOT=/home/ram/rpmbuild

Is it correct?.

Please clarify my doubts on RPM packaging.

Thank you.