From Slashdot :
“In Java 1.6.0_21, the company field was changed from ‘Sun Microsystems, Inc’ to ‘Oracle.’ Apparently not the best idea, because some applications depend on that field to identify the virtual machine. All Eclipse versions since 3.3 (released 2007) until and including the recent Helios release (2010) have been reported to crash with an OutOfMemoryError due to this change. This is particularly funny since the update is deployed through automatic update and suddenly applications cease to work.”
We probably need to check how DrJava behaves , too.
Oracle now says that the rebranding will not happen until Java 7  is released:
In consideration to Eclipse and other potentially affected users, Oracle has restored the Windows Company Name property value to “Sun Microsystems”. This value will be changed to “Oracle” in JDK 7.
I actually misunderstood the problem. DrJava would not have been affected at this time because the java.vm.vendor property wasn’t changed. It will change with Java 7, though.