In case you've been experiencing frequent crashes like me despite every possible jvm/eclipse tuning, see:
http://jojava.blogspot.com/2011/05/jvm-crashes-with-6u25-c2-tiered.html
https://community.dynatrace.com/community/display/PUB/Jave+6+Update+25+p...
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7040769
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7042582
http://www.oracle.com/technetwork/java/javase/6u25releasenotes-356444.html
Eclipse seems to be extremely sensitive to his issue...