NullPointerException in PDEState.querySystemPackages

[laeubi]

I have updates my SDK an now getting NPE

java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:208)
	at java.base/java.lang.String.join(String.java:3320)
	at org.eclipse.pde.internal.build.site.PDEState.querySystemPackages(PDEState.java:548)
	at org.eclipse.pde.internal.build.site.PDEState.getSystemPackages(PDEState.java:491)
	at org.eclipse.pde.internal.core.TargetPlatformHelper.getSystemPackages(TargetPlatformHelper.java:391)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.initialize(ApiBaseline.java:295)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.initialize(ApiBaseline.java:243)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.resolveSystemLibrary(ApiBaseline.java:471)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.addApiComponents(ApiBaseline.java:418)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.restoreFrom(ApiBaseline.java:763)
	at org.eclipse.pde.api.tools.internal.ApiBaselineManager.loadBaselineInfos(ApiBaselineManager.java:242)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.loadBaselineInfos(ApiBaseline.java:735)
	at org.eclipse.pde.api.tools.internal.model.ApiBaseline.getApiComponents(ApiBaseline.java:519)
	at org.eclipse.oomph.setup.pde.impl.APIBaselineFromTargetTaskImpl.isNeeded(APIBaselineFromTargetTaskImpl.java:263)
	at org.eclipse.oomph.setup.internal.core.SetupTaskPerformer.initNeededSetupTasks(SetupTaskPerformer.java:2285)
	at org.eclipse.oomph.setup.ui.SetupUIPlugin.performStartup(SetupUIPlugin.java:811)
	at org.eclipse.oomph.setup.ui.SetupUIPlugin$1$1.run(SetupUIPlugin.java:266)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

[laeubi]

I also get now constantly "An internal error occurred during: "Initializing plug-in models".

java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:208)
	at java.base/java.lang.String.join(String.java:3320)
	at org.eclipse.pde.internal.build.site.PDEState.querySystemPackages(PDEState.java:548)
	at org.eclipse.pde.internal.build.site.PDEState.getSystemPackages(PDEState.java:491)
	at org.eclipse.pde.internal.core.TargetPlatformHelper.getSystemPackages(TargetPlatformHelper.java:391)
	at org.eclipse.pde.internal.core.TargetPlatformHelper.addEnvironmentProperties(TargetPlatformHelper.java:378)
	at org.eclipse.pde.internal.core.TargetPlatformHelper.getPlatformProperties(TargetPlatformHelper.java:365)
	at org.eclipse.pde.internal.core.MinimalState.initializePlatformProperties(MinimalState.java:251)
	at org.eclipse.pde.internal.core.PDEState.<init>(PDEState.java:70)
	at org.eclipse.pde.internal.core.PluginModelManager.initializeTable(PluginModelManager.java:617)
	at org.eclipse.pde.internal.core.PluginModelManager.targetReloaded(PluginModelManager.java:542)
	at org.eclipse.pde.internal.core.RequiredPluginsInitializer.lambda$0(RequiredPluginsInitializer.java:33)
	at org.eclipse.core.runtime.jobs.Job$2.run(Job.java:187)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)

[HannesWell]

I have updates my SDK an now getting NPE

Could you please check in which scenario (VMInstall + EE + EE-default) this happen.
Actually the code should handle the null Case so probably another null-check ist sufficient. Could you provide a PR to fix this?

[laeubi]

This happens when a JVM can't be queried for system packages, you can simulate this by having a JDK for an EE and delete the release file, see this bug:

• An internal error occurred during: "Java Search" eclipse-jdt/eclipse.jdt.core#1154

this fixed it on the JDT part but now PDE suffers from this as it somewhere gets a null

also see here why its hard to recover from such state:

• Removing an automatic added JVM brings it back after restart eclipse-jdt/eclipse.jdt.debug#404

[HannesWell]

Ok. Could please provide a PR with an extra null check?

[HannesWell]

I had a quick look at this and while an extra null check would fix the NPE you will likely have follow-up errors because you then have no system-packages provided for that EE and all bundles with that EE that import system-packages will fail to resolve.

So to really fix this all VMs suitable for an EE have to be queried until one returns non-null system packages.
In general it would be good if JDT would sort the VMs of an EE by 'completeness', e.g. by the number of provided system-packages. This would probably also improve the auto-selection used for the VM-Install of an JRE Classpath-container. Then for example the VM contained in Jextract is very unlikely to be used (I had issues once when this happened and all of a sudden many projects failed to compile).

This actually not really a regression from #693 because for modular JDK the same logic was used before.

[jukzi]

Now i get Warnings on every IDE start. "No JVM system-packages available for environment "
And they are too many. Not even distinct. And why do i get that warnings at all? I did not try to use any 18+ stuff

[laeubi]

@jukzi I think this is a different issue than the NPE and might better be handled in a separate issue.