The most important new features in the JDT are:
Rich hovers:
Follow links in Javadoc hover
Quick fix problems in problem hover
Inspect variable values in the debug hover
Java Editor Breadcrumb: Know where you are while in the editor
Various Content Assist improvements
SWT Templates: Build your UI the fast way
Format edited lines on save: Keep outgoing changes to a minimum
Extract Class refactoring: Replace a set of fields by a new class
Compiler supports multi CPU-machines: Compile your workspace faster
