There are many Java IDEs. The most popular three are;
- Netbeans - open source IDE in Java for Java. Supports Swing better.
- Eclipse - open source IDE in Java for Java. Supports SWT better.
- IntelliJ IDEA - open source community edition. Has everything needed for game development with JavaSE
Other Java IDEs
- IntelliJ IDEA Ultimate - commercial edition. Has support for JavaEE frameworks, i.e. hibernate, gwt. Not needed for game development
- producers of JDKs: from Sun, from IBM, from ...
- "hard" Real Time support via RTSJ: from Sun, from IBM, from TimeSys
- J2ME, J2SE, J2EE