Eclipse is not just an IDE, it is also a framework, much like springboard and .NET.
Also, VS would work as and editor for java files...but I digress.
Yes, Eclipse is very popular with the OSS community, for good reason, but if your just starting out with java, I would suggest getting the bundled package from sun.com. It's the sdk, documentation, and the Netbeans IDE. Netbeans is good in it's own right.