Fix possible NPE in maven ModuleInfoSelector

[mbien]

SourceLevelQuery may return null. (e.g if the version string isn't valid)

code section was introduced a while ago #2037

fixes #9180

[neilcsmith-net]

Makes sense, thanks!

Aside - looking at uses of System.getProperty("java.version") suggests we might have quite a few things that could be removed in future.

[lahodaj]

I guess I wonder the "polarity" should be reversed, i.e. if there's no source level, then maybe we should consider the source level to be 9+ nowadays? Or does that have some known severe impact?

[mbien]

I guess I wonder the "polarity" should be reversed, i.e. if there's no source level, then maybe we should consider the source level to be 9+ nowadays? Or does that have some known severe impact?

like

if (sourceLevel == null || !sourceLevel.startsWith("1.")) { //NOI18N
    // both sourceLevel and ideJDK are 9+
    ret = hasModuleInfoCP.get();  
}

?

changing the bias should be possible I think. But I am not sure why the source level query exists in the first place, if there is a module-info file, it can't be <=8 anymore which seems to be the purpose of the check.

I would prefer to keep it as is for NB 29 and consider reverting #2037 for NB 30.

[neilcsmith-net]

I had actually written the same thing as @lahodaj in my comment, and then decided to remove before posting for a similar reason that it's probably better to keep the code like this for NB29 and review more later.

[ebarboni]

will merge this as more works will be done in NB30