The NetBeans IDE 6.1 Beta is out now, and it seems like the NetBeans developers have been very busy. In general there are big improvements on NB start-up time (shorter start-up = always nice), there is faster and smarter code completion and a reduction in the memory consumption.
JavaScript has been supported even better; with semantic highlighting, code completion, type analysis, quick fixes, semantic checks, and support for refactoring - that GREAT news for every JavaScript programmer as we all know how error prone JavaScripts can be.
Better or added support for the following technologies is also included:
-Spring Framework Support
-MySQL
-Ruby/JRubys
-Java Beans
See more here