Eclipse 3.1 M6

The folks on the Eclipse development team are going full throttle. They’re putting
 the finishing touches on version 3.1. Less than two months separate 
 the previous milestone, M5, from the current M6. No wonder, since the 3.1 series is meant to bring full support 
 for Java 5.0, an area where this IDE, compared with its competitors, 
 rather fell asleep at the wheel. It’s hard to say whether that was down to the work 
 of getting the transitional version 3 ready, but the lack of Java 5.0 support is hard 
 to understand.

Here’s what’s new in M6. Eclipse 3.1 M6 — New and Noteworthy

Based on my experience with previous releases and milestones, I’m going to wait 
 a little longer before upgrading. The memory appetite and sluggishness 
 of some of those milestones are reason enough for me to hold off.
 Plug-in compatibility shouldn’t be a problem, though, since the core API is supposed only to grow.