Occasional NPE when opening / importing / creating Maven projects

[brianvfernandes]

In STS 4.22.1, occasionally, when opening a Maven project or importing/creating one, the following trace is logged as an error.

java.lang.NullPointerException: Cannot invoke "org.eclipse.m2e.core.project.IMavenProjectFacade.getArtifactKey()" because "facade" is null
	at org.springframework.tooling.jdt.ls.commons.classpath.ClasspathUtil.createProjectBuild(ClasspathUtil.java:235)
	at org.springframework.tooling.jdt.ls.commons.classpath.SendClasspathNotificationsJob.run(SendClasspathNotificationsJob.java:146)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

I'm unsure what the impact of this error is.

To Reproduce
The error does not occur always, you may need multiple attempts of closing and opening a Maven project or creating one before you see it in the log.

It appears to be a race condition where the above code attempts to get Maven metadata before the Maven registry has fully processed the project (as it too is reacting to a new project being available in the workspace).

[BoykoAlex]

Rework of how GAV are computed for projects pushed in with: ba6fc2a Should fix the NPE reported here.

[brianvfernandes]

That's quite a change! I have also run into the following NPE occasionally - it occurs only once per session; again, appears to be a race condition. Would this also be fixed by the GAV rework? Please let me know if I should file another issue.

!MESSAGE NullPointerException: Cannot invoke "org.springsource.ide.eclipse.commons.livexp.core.LiveSetVariable.getValue()" because "this.this$0.applications" is null
!STACK 0
java.lang.NullPointerException: Cannot invoke "org.springsource.ide.eclipse.commons.livexp.core.LiveSetVariable.getValue()" because "this.this$0.applications" is null
	at org.springframework.ide.eclipse.boot.dash.model.LocalBootDashModel$2.bundleChanged(LocalBootDashModel.java:157)
	at org.eclipse.osgi.internal.framework.BundleContextImpl.dispatchEvent(BundleContextImpl.java:972)
	at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
	at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:341)```

[BoykoAlex]

No the NPE above is not related to GAVs. It is a straight-forward NPE fix: 6de76d8