Java 100 % CPU usage
You're running a program. It's using resources. If you want a program to run, it runs using any resources it needs as available. This is the intended behavior.

If you want to limit the resources available to your IDE, you can do that. Limiting the resources provided is pretty easy (provided you're willing to work with a little bit of third-party software.) You can use cputhrottle to limit the usage at the system level (better explained here.)