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im gona learn JAVA
Java, huh? You're getting way in over your head. Start simple, then work your way up. Maybe you'll even be able to develop your own languages like me.
As far as Java goes, if you really want to start there, and you actually want to write your own programs, not some cheesy RSBot script, you'll need an IDE of some sort or the JDK and some lightweight editor. You should use Eclipse or Netbeans, as those are the better known Java development environments. If you do, you probably won't need JDK.