Oracle claims NetBeans 7 is the first open source IDE to support the next-generation Java platform.

Support for Java 7 standard edition (SE) is the focus of the new toolset and Oracle claims it is the first open-source IDE to support the JDK 7 preview.

If you are using NetBeans 6.1 builds then you can deploy your Rails application directly on GlassFish v3 from within NetBeans IDE .