Add note about JDK6 on OS X

[TheSpyder]

As discussed in issue #90. Regardless of how it is compiled, at runtime using JNI on OS X requires Java 6.

[jsdevel]

@TheSpyder I'm able to compile on OS X when my java home references 1.7. Are you saying that 1.6 must be installed as well? I'm not sure this PR was accurate because of that.

[TheSpyder]

I guess it wouldn't make much sense unless you read the comment I linked to in the readme. Sorry :)

While you can compile using JDK7 quite happily with the changes made in 0.3.4, at runtime the OS forces the use of JDK6. It's actually an Oracle JDK bug. You can test this by deleting (or moving) /System/Library/Java/JavaVirtualMachines/1.6.0.jdk and then running an app that uses node-java. The system will prompt you to install Java 6 regardless of how node-java is compiled (unless you use the workarounds I mention in the comment).

[jsdevel]

Thanks for the clarification @TheSpyder. If that's the case, then i think the README should be updated to say that jdk6 is required at runtime.

[jsdevel]

@TheSpyder there were a lot of comments listed in #90. Can you recap here on how we can reproduce the issue? Would removing JDK6 from my system recreate the issue for me?

[TheSpyder]

There were a lot of comments, but the readme link I added specifically navigates to to my big comment explaining my research rather than the issue in general.

If you remove the folder I mentioned above you can reproduce the issue.

Given that JDK6 is required at runtime, I'm not sure there is much point in supporting other versions of Java for installation - but that's your call :)

[jsdevel]

Thanks @TheSpyder. I updated the README and added a separate section for OSX users. Thanks again for your help!

[TheSpyder]

Cool. You misspelt installation though :)

[jsdevel]

0c23c77 👍