Licensing

I have a few questions on licensing software:

1. Do I have to put my license on every file if its open source? Including the XML/LUA code?
a. Do I also have to do this for every license?
b. Is there any application or eclipse plugin to do this?

2. Can I rename my libraries licenses? Like “LICENSE” to “JDOM-LICENSE”
a. Can they be in a seperate folder? Like licenses or do they HAVE to be in my classpath?