JVM should print a warning message that -Xshare:on may cause VM to abort start-up

CDS maps the archive file at a fixed address. On some platforms, especially Windows and 32-bit Linux, there's a chance that, with address space layout randomization, the CDS address may have been occupied by a system DLL before the JVM starts. In this case, CDS mapping will fail. -Xshare:auto continue to execute (with CDS enabled), but -Xshare:on will exit the JVM.

The mapping failure is much more rare on 64-bit Linux, but nevertheless, in a production environment, you should use -Xshare:auto and not -Xshare:on.

This behavior -Xshare:on option is very much a legacy feature that was not well designed.

The JVM should at least print out a warning message. Or better, make -Xshare:on behave the same as -Xshare:auto (but a lot of our tests depend on the -Xshare:on failure mode), so doing that would require more work.