Add support for -X JVM options

[malliina]

If you specify JVM options starting with "-X" in javaOptions in Universal, such as

-Xbootclasspath/p:/usr/share/appname/lib/org.mortbay.jetty.alpn.alpn-boot-8.1.11.v20170118.jar

Then the bash script will append the option too late in the java command, and it won't work. This commit fixes it. Similar to #431.

[muuki88]

Thanks for your pull request.

IIRC you can append JVM parameters by starting with -J, e.g. -J-Xmx512mb. If this is not working for you then we should open a bug to fix this.

[malliina]

Thanks for the suggestion, I tried prepending -J, however it didn't work. I believe in this case the example -X parameter above needs to be treated like app parameters similar to -D params.

What does work is the following:

bashScriptExtraDefines += s"""addJava "-Xbootclasspath/p:/usr/share/app/lib/file.jar""""

I interpreted from the docs that an equivalent way to define that is:

javaOptions in Universal += "-Xbootclasspath/p:/usr/share/app/lib/file.jar"

or then

javaOptions in Universal += "-J-Xbootclasspath/p:/usr/share/app/lib/file.jar"

However, neither of the javaOptions ... approaches work in this case (but maybe the -J params do work for JVM memory settings). Effectively the desired java run command would look like:

java -Xbootclasspath/p:/usr/share/appname/lib/file.jar -Dexample.prop=example.value -Dother=values and so on...

And that's only the case for me if I add the parameter using bashScriptExtraDefines above. Well, since the bashScriptExtraDefines approach works for me I'll survive, but I thought this was quite confusing to configure as it is.

[dwickern]

Looking at the code, -J-X should be equivalent to addJava -X 🤔

[malliina]

Yeah you are correct, sorry for wasting your time with this PR. I had a problem in my deployment process where changes to JVM parameters didn't propagate properly in all cases.

[muuki88]

No worries ☺️