WrongMethodTypeException with blackbird

[naveg]

After upgrading to Java 16 and Jackson 2.12 with Blackbird replacing Afterburner, we are seeing WrongMethodTypeException occur frequently. The strange thing is that this affects only 25-40% of requests. An identical request made repeatedly will fail at that rate.

Example stack trace:

java.lang.invoke.WrongMethodTypeException: expected ()ToIntFunction but found ()ToIntFunction
	at java.base/java.lang.invoke.Invokers.newWrongMethodTypeException(Invokers.java:506)
	at java.base/java.lang.invoke.Invokers.checkExactType(Invokers.java:515)
	at com.fasterxml.jackson.module.blackbird.ser.BBSerializerModifier.createProperty(BBSerializerModifier.java:116)
	at com.fasterxml.jackson.module.blackbird.ser.BBSerializerModifier.lambda$findProperties$0(BBSerializerModifier.java:64)
	at com.fasterxml.jackson.module.blackbird.util.Unchecked.lambda$runnable$0(Unchecked.java:31)
	at com.fasterxml.jackson.module.blackbird.ser.BBSerializerModifier.findProperties(BBSerializerModifier.java:65)
	at com.fasterxml.jackson.module.blackbird.ser.BBSerializerModifier.changeProperties(BBSerializerModifier.java:49)
	at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.constructBeanOrAddOnSerializer(BeanSerializerFactory.java:407)
	at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.findBeanOrAddOnSerializer(BeanSerializerFactory.java:290)
	at com.fasterxml.jackson.databind.ser.BeanSerializerFactory._createSerializer2(BeanSerializerFactory.java:235)
	at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.createSerializer(BeanSerializerFactory.java:169)
	at com.fasterxml.jackson.databind.SerializerProvider._createUntypedSerializer(SerializerProvider.java:1473)
	at com.fasterxml.jackson.databind.SerializerProvider._createAndCacheUntypedSerializer(SerializerProvider.java:1421)
	at com.fasterxml.jackson.databind.SerializerProvider.findContentValueSerializer(SerializerProvider.java:753)
	at com.fasterxml.jackson.databind.ser.impl.PropertySerializerMap.findAndAddSecondarySerializer(PropertySerializerMap.java:90)
	at com.fasterxml.jackson.databind.ser.std.AsArraySerializerBase._findAndAddDynamic(AsArraySerializerBase.java:311)
	at com.fasterxml.jackson.databind.ser.impl.IndexedListSerializer.serializeContents(IndexedListSerializer.java:115)
	... 74 common frames omitted

This is occuring in a Dropwizard application.

Happy to provide more information as needed, and will continue to dig and update this issue with what I find.

[cowtowncoder]

cc @stevenschlansker

[stevenschlansker]

This is a strange exception message. ToIntFunction is part of java.base so there should never be more than one...
Do you have a reproducible test case you can share? What does the definition of the type you serialize look like?

[stevenschlansker]

@naveg , a couple more questions: do you use any custom or non-default classloaders, or set the thread context class loader ever?

[stevenschlansker]

@naveg , I would love to help fix this issue, but we will need some more information (some questions above) or ideally a self contained test case showing the issue to dig in - I have never seen an exception like this myself.

[cowtowncoder]

Cannot reproduce, no more info added, closing. May be reopened/refiled with necessary info.