Target errors when running in parallel

[laeubi]

The problem seems to be that the target file dom is accessed from multiple threads and this fails.

I run the build with -T=8

Caused by: java.lang.IllegalArgumentException: java.lang.IllegalArgumentException: type: -1
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at java.base/java.util.concurrent.ForkJoinTask.getThrowableException(ForkJoinTask.java:600)
	at java.base/java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:678)
	at java.base/java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:737)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateParallel(ForEachOps.java:159)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateParallel(ForEachOps.java:173)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:233)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
	at org.eclipse.tycho.core.maven.TychoMavenLifecycleParticipant.lambda$resolveProjects$2(TychoMavenLifecycleParticipant.java:161)
	at java.base/java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1407)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)
Caused by: java.lang.IllegalArgumentException: type: -1
	at java.xml/com.sun.org.apache.xerces.internal.dom.DeferredDocumentImpl.getNodeObject(DeferredDocumentImpl.java:1063)
	at java.xml/com.sun.org.apache.xerces.internal.dom.DeferredDocumentImpl.synchronizeChildren(DeferredDocumentImpl.java:1723)
	at java.xml/com.sun.org.apache.xerces.internal.dom.DeferredElementImpl.synchronizeChildren(DeferredElementImpl.java:136)
	at java.xml/com.sun.org.apache.xerces.internal.dom.ParentNode.getChildNodes(ParentNode.java:217)
	at org.eclipse.tycho.p2.target.facade.TargetDefinitionFile.getChildren(TargetDefinitionFile.java:383)
	at org.eclipse.tycho.p2.target.facade.TargetDefinitionFile.getLocations(TargetDefinitionFile.java:573)
	at org.eclipse.tycho.p2.target.TargetDefinitionResolver.resolveContentWithExceptions(TargetDefinitionResolver.java:136)
	at org.eclipse.tycho.p2.target.TargetDefinitionResolver.resolveContent(TargetDefinitionResolver.java:109)
	at org.eclipse.tycho.p2.target.TargetDefinitionResolverService.resolveFromArguments(TargetDefinitionResolverService.java:89)
	at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1705)
	at org.eclipse.tycho.p2.target.TargetDefinitionResolverService.getTargetDefinitionContent(TargetDefinitionResolverService.java:62)
	at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.resolveTargetDefinitions(TargetPlatformFactoryImpl.java:215)
	at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.createTargetPlatform(TargetPlatformFactoryImpl.java:157)
	at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.createTargetPlatform(TargetPlatformFactoryImpl.java:127)
	at org.eclipse.tycho.p2.target.TargetPlatformFactoryImpl.createTargetPlatform(TargetPlatformFactoryImpl.java:1)
	at org.eclipse.tycho.p2.manager.ReactorRepositoryManagerImpl.computePreliminaryTargetPlatform(ReactorRepositoryManagerImpl.java:86)
	at org.eclipse.tycho.p2.resolver.P2DependencyResolver.computePreliminaryTargetPlatform(P2DependencyResolver.java:226)
	at org.eclipse.tycho.core.resolver.DefaultTychoResolver.resolveProject(DefaultTychoResolver.java:125)
	at org.eclipse.tycho.core.maven.TychoMavenLifecycleParticipant.lambda$resolveProjects$0(TychoMavenLifecycleParticipant.java:147)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
	at java.base/java.util.stream.SpinedBuffer$1Splitr.forEachRemaining(SpinedBuffer.java:364)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
	at java.base/java.util.stream.ForEachOps$ForEachTask.compute(ForEachOps.java:290)
	at java.base/java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:746)
	... 5 more

[laeubi]

Duplicate of #496