Java fails with Class Data Sharing

I tried running Java and got the following error:

java.exe Application Error
The instruction at "0x6d8ba31a" referenced memory at "0x00000040". The memory could not be "read".

The ReactOS SVN revision I built was 41171.
Using Virtualbox 2.2.2 r46594

Steps to reproduce, on a 'clean install' of ReactOS:
1. Download the JDK 1.6 installer, e.g. jdk-6u13-windows-i586-p.exe from http://java.sun.com/javase/downloads/index.jsp
2. Double click on the installer. A bunch of incomplete screens appear but clicking on the forward arrows to advance the wizard does in fact install the software. Click Finish!
3. Open a command line.
4. enter 'java -version'. The first time, the JVM will output the version information, as expected.
5. enter 'java -version' again. The above error message appears.

I wondered why it would work the first time but not subsequently, it turns out Java's Hotspot virtual machine loads java classes into shared memory as described here:

http://java.sun.com/javase/6/docs/technotes/guides/vm/class-data-sharing.html

launching java as above with the -Xshare:off option as specified in the docs prevents the error message, on a per invocation basis. I'm not aware it's possible to turn it off permanently as a workaround to this bug... Further executing 'java -Xshare:dump' does clear the memory sharing, allowing the first invocation to work as in Step 4.