First-class IDE support has been one of Scala's sore spots. Although all the major Java IDEs, including Eclipse, NetBeans, and IntelliJ IDEA, support Scala development, working with Scala in these IDEs is not as polished an experience as coding Java is via these tools. The Scala IDE landscape, however, is changing fast, with improved tools being released at a steady clip.
The latest major Scala tools upgrade occurred as part of the Scala's 2.7.4 release candidate. One of the main challenges the Scala IDE for Eclipse aims to address is the ease with which Java and Scala projects can be combined:
This release is based on a new approach to integration with the Eclipse JDT which makes use of Equinox Aspects and the JDT weaving functionality developed in conjunction with Andrew Eisenberg of AJDT.
This allows for much deeper and more robust interoperation between Eclipse's Scala and Java tooling. As a result many long standing bugs have been resolved ... and many additional JDT features will now work correctly with Scala projects.
From 2.7.4 onwards the new name for the plugin is the Scala IDE for Eclipse...
Those with an existing Eclipse installation can access the latest Scala IDE from the project's Eclipse update site.
What do you think of the current state of Scala tools support?
The NetBeans plugin is usable but clearly needs more work. Most obvious flaw (to me) is that it doesn't recompile all the necessary files after a change. Admittedly even IDEA sometimes still gets this wrong for Java. I don't know about the state of the others.