Not compatible with GraalVM

[ivansenic]

Trying to build a native image for the application that uses this schema validator, fails with the following exception:

Fatal error: org.graalvm.compiler.debug.GraalError: com.oracle.graal.pointsto.constraints.UnsupportedFeatureException: Detected a started Thread in the image heap. Threads running in the image generator are no longer running at image runtime.  Object has been initialized by the com.github.fge.jsonschema.cfg.ValidationConfigurationBuilder class initializer with a trace: 
 	at java.lang.Thread.<init>(Thread.java:708)
	at java.util.concurrent.Executors$DefaultThreadFactory.newThread(Executors.java:660)
	at com.github.fge.msgsimple.provider.LoadingMessageSourceProvider$1.newThread(LoadingMessageSourceProvider.java:91)
	at java.util.concurrent.ThreadPoolExecutor$Worker.<init>(ThreadPoolExecutor.java:630)
	at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:920)
	at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1353)
	at com.github.fge.msgsimple.provider.LoadingMessageSourceProvider.getMessageSource(LoadingMessageSourceProvider.java:190)
	at com.github.fge.msgsimple.bundle.MessageBundle.getMessage(MessageBundle.java:122)
	at com.github.fge.msgsimple.bundle.MessageBundle.getMessage(MessageBundle.java:146)
	at com.github.fge.jackson.JsonNodeReader.readNode(JsonNodeReader.java:147)
	at com.github.fge.jackson.JsonNodeReader.fromInputStream(JsonNodeReader.java:101)
	at com.github.fge.jackson.JsonLoader.fromURL(JsonLoader.java:122)
	at com.github.fge.jsonschema.SchemaVersion.<init>(SchemaVersion.java:66)
	at com.github.fge.jsonschema.SchemaVersion.<clinit>(SchemaVersion.java:45)
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Unknown Source)
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:568)
	at java.lang.Class.getEnumConstantsShared(Class.java:3837)
	at java.lang.System$2.getEnumConstantsShared(System.java:2284)
	at java.util.EnumMap.getKeyUniverse(EnumMap.java:747)
	at java.util.EnumMap.<init>(EnumMap.java:135)
	at com.google.common.collect.Maps.newEnumMap(Maps.java:423)
	at com.github.fge.jsonschema.cfg.ValidationConfigurationBuilder.<clinit>(ValidationConfigurationBuilder.java:62)
. Try avoiding to initialize the class that caused initialization of the Thread. The object was probably created by a class initializer and is reachable from a static field. You can request class initialization at image runtime by using the option --initialize-at-run-time=<class-name>. Or you can write your own initialization methods and call them explicitly from your main entry point.
	at com.oracle.graal.pointsto.util.AnalysisFuture.setException(AnalysisFuture.java:49)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:269)
	at com.oracle.graal.pointsto.util.AnalysisFuture.ensureDone(AnalysisFuture.java:63)
	at com.oracle.graal.pointsto.heap.ImageHeapScanner.lambda$postTask$9(ImageHeapScanner.java:611)
	at com.oracle.graal.pointsto.util.CompletionExecutor.executeCommand(CompletionExecutor.java:193)
	at com.oracle.graal.pointsto.util.CompletionExecutor.lambda$executeService$0(CompletionExecutor.java:177)
	at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1395)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)

Used GraalVM props:

 Version info: 'GraalVM 22.1.0 Java 17 CE'
 C compiler: gcc (redhat, x86_64, 8.5.0)