rare NPE in classpath listener

[martinlippert]

It seems like I have hit a rare moment in time where the editor for the pom.xml file wasn't fully initialized yet when we tried to grab classpath information:

java.lang.NullPointerException: Cannot invoke "org.eclipse.ui.texteditor.ITextEditor.getAdapter(java.lang.Class)" because "this.sourcePage" is null
	at org.eclipse.m2e.editor.pom.MavenPomEditor.getAdapter(MavenPomEditor.java:1013)
	at org.springframework.tooling.ls.eclipse.commons.STS4LanguageClientImpl.lambda$9(STS4LanguageClientImpl.java:423)
	at org.springframework.tooling.jdt.ls.commons.classpath.ReusableClasspathListenerHandler$CallbackJob.lambda$0(ReusableClasspathListenerHandler.java:76)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at org.springframework.tooling.jdt.ls.commons.classpath.ReusableClasspathListenerHandler$CallbackJob.run(ReusableClasspathListenerHandler.java:76)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

This is probably hard to reproduce. It happened when I created a Rest Service sample project right after starting up a fresh install of STS 4.17.2 with a fresh workspace, opened the pom.xml file, and pressed Yes on the reconcile popup - almost everything at the same time.

[BoykoAlex]

It would have been best if MavenPomEditor doesn't throw an NPE in this case: eclipse-m2e/m2e-core#1235

On our side i think we should catch and log exceptions without short-circuiting the loop: 5d9eee9

[BoykoAlex]

I'll close it. Also pushed logic to update code minings on classpath changed event only for editors for resources from classpath source folders. Thus, pom are filtered out (27e08f9). It looks like a fair assumption for the moment. Thus, pom editors are not applicable to this code any longer.