ClassCastException: class org.entur.lamassu.model.entities.Vehicle

[hbruch]

When starting up Lamassu, occasionally ClassCastExceptions get logged which are apparently caused by SpringBoot's devtools classloading (see e.g. this stackoverflow thread):

java.lang.ClassCastException: null
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
	at java.base/java.util.concurrent.ForkJoinTask.getThrowableException(ForkJoinTask.java:564)
	at java.base/java.util.concurrent.ForkJoinTask.reportException(ForkJoinTask.java:591)
	at java.base/java.util.concurrent.ForkJoinTask.invoke(ForkJoinTask.java:689)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateParallel(ForEachOps.java:159)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateParallel(ForEachOps.java:173)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:233)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:596)
	at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:765)
	at org.entur.gbfs.GbfsSubscriptionManager.lambda$update$0(GbfsSubscriptionManager.java:68)
	at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1395)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
Caused by: java.lang.ClassCastException: class org.entur.lamassu.model.entities.Vehicle cannot be cast to class org.entur.lamassu.model.entities.Vehicle (org.entur.lamassu.model.entities.Vehicle is in unnamed module of loader 'app'; org.entur.lamassu.model.entities.Vehicle is in unnamed module of loader org.springframework.boot.devtools.restart.classloader.RestartClassLoader @5185ac30)
	at org.entur.lamassu.leader.entityupdater.VehiclesUpdater.lambda$addOrUpdateVehicles$4(VehiclesUpdater.java:140)
	at java.base/java.util.HashMap.forEach(HashMap.java:1421)
	at org.entur.lamassu.leader.entityupdater.VehiclesUpdater.addOrUpdateVehicles(VehiclesUpdater.java:138)
	at org.entur.lamassu.leader.entityupdater.EntityCachesUpdater.updateEntityCaches(EntityCachesUpdater.java:46)
	at org.entur.lamassu.leader.FeedUpdater.receiveUpdate(FeedUpdater.java:133)
	at org.entur.lamassu.leader.FeedUpdater.lambda$createSubscription$1(FeedUpdater.java:113)
	at org.entur.gbfs.GbfsSubscription.update(GbfsSubscription.java:104)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
	at java.base/java.util.concurrent.ConcurrentHashMap$ValueSpliterator.forEachRemaining(ConcurrentHashMap.java:3612)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.ForEachOps$ForEachTask.compute(ForEachOps.java:290)
	at java.base/java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:754)
	... 5 common frames omitted

I'm unsure about the impact of this exception, but for production deployments devtools should explicitly not be packaged. Another option would be to disable devtools restart by adding spring.devtools.restart.enabled = false to application.properties.

[testower]

Yes I have also noticed this, but not yet found a solution.

[hbruch]

Consequence of this error seems to be, that caches are cleared, it seems to me. As this seems to happen only in dev mode with spring devtools enabled, that would not impact production.

[testower]

Yeah possibly a conflict between spring dev tools and kryo. Keeping the issue open just for clarity.