How can I securely wipe a confidential data in memory in java with guarantee it will not be 'optimized'?

Question

String secret=\"foo\";
WhatILookFor.securelyWipe(secret);

And I need to know that it will not be removed by java optimizer.

Answer 1

Store the data off-heap using the "Unsafe" methods. You can then zero over it when done and be certain that it won't be pushed around the heap by the JVM.

Here is a good post on Unsafe:

http://highlyscalable.wordpress.com/2012/02/02/direct-memory-access-in-java/