Implement maven pom javac release option hint (JEP 247).

[mbien]

• converts matching source/target options to the release option
• supports properties and the standard maven-compiler-plugin
• offers only hints when source/release is set to at least 9+ (could be improved in future once I figure out how to query the JDK version of the project)

It is fairly basic and has a small cosmetic issue. I don't know how to replace elements in-place, so it simply adds the release element to the end of the list if the hint is applied, no matter where source/target was.

I also don't know how to apply hints in the junit tests. When I tried to do that it complained that the model was read only (org.netbeans.modules.xml.xam.dom.ReadOnlyAccess). I suppose its a dummy model.

How to test:
create a new java project and it should already show the hint. It only looks for properties and the config of the standard javac plugin.

[mbien]

oops. forgot the license headers. Let me fix this :)

[ebarboni]

if maven-compiler-plugin version is <3.6 it would not be able to use the release parameter.

[mbien]

if maven-compiler-plugin version is <3.6 it would not be able to use the release parameter.

@ebarboni good to know! How do I compare versions? Is there a utility for this?

there would be this:
https://maven.apache.org/ref/3.6.3/maven-artifact/apidocs/org/apache/maven/artifact/versioning/ComparableVersion.html
but this module does not use that API.

edit: added a little utility method which checks compatibility

[mbien]

@matthiasblaesing do you have any remaining concerns integrating this in the current form or should we move it to NB17?

[mbien]

fixed potential NPE when artifactID is null

[matthiasblaesing]

@matthiasblaesing do you have any remaining concerns integrating this in the current form or should we move it to NB17?

No problem - with the reasoning that 8 is dead and thus release will always be there, we are only missing a corner-case. The approach for the properties seems reasonable.

[mbien]

@neilcsmith-net is master already branched? Or can I still merge?

[neilcsmith-net]

@mbien you have about 10 minutes! 😄

[mbien]

awesome merged. Usually I would wait for approval but I think I addressed all review comments and implemented everything. If there is an issue left, it probably not going to be a big one and I can fix it during RC.