RESTEASY008200: JSON Binding deserialization error: No default constructor

Describe the bug I get the error described in https://github.com/quarkusio/quarkus/issues/3179. The issue was closed as it should be resolved with quarkus 1.0 Final and its dependency yasson 1.0.5. But error is still there. I cannot add a no args constructor because the class is defined within an external dependency (library).

javax.ws.rs.ProcessingException: RESTEASY008200: 
JSON Binding deserialization error: javax.json.bind.JsonbException:  Can't create instance of a class: class com.domain.Task, No default constructor found.
		at org.jboss.resteasy.plugins.providers.jsonb.JsonBindingProvider.readFrom(JsonBindingProvider.java:78)
	at org.jboss.resteasy.core.interception.jaxrs.AbstractReaderInterceptorContext.readFrom(AbstractReaderInterceptorContext.java:102)
	at org.jboss.resteasy.core.interception.jaxrs.AbstractReaderInterceptorContext.proceed(AbstractReaderInterceptorContext.java:81)
	at org.jboss.resteasy.client.jaxrs.internal.ClientResponse.readFrom(ClientResponse.java:226)
	at org.jboss.resteasy.specimpl.BuiltResponse.readEntity(BuiltResponse.java:88)
	at org.jboss.resteasy.specimpl.AbstractBuiltResponse.readEntity(AbstractBuiltResponse.java:270)
...
Caused by: javax.json.bind.JsonbException: Can't create instance of a class: class com.domain.Task, No default constructor found.
	at org.eclipse.yasson.internal.serializer.ObjectDeserializer.getInstance(ObjectDeserializer.java:95)
	at org.eclipse.yasson.internal.serializer.AbstractContainerDeserializer.deserialize(AbstractContainerDeserializer.java:61)
	at org.eclipse.yasson.internal.serializer.CollectionDeserializer.deserializeNext(CollectionDeserializer.java:106)
	at org.eclipse.yasson.internal.serializer.AbstractContainerDeserializer.deserializeInternal(AbstractContainerDeserializer.java:84)
	at org.eclipse.yasson.internal.serializer.AbstractContainerDeserializer.deserialize(AbstractContainerDeserializer.java:60)
	at org.eclipse.yasson.internal.Unmarshaller.deserializeItem(Unmarshaller.java:68)
	at org.eclipse.yasson.internal.Unmarshaller.deserialize(Unmarshaller.java:54)
	at org.eclipse.yasson.internal.JsonBinding.deserialize(JsonBinding.java:53)
	at org.eclipse.yasson.internal.JsonBinding.fromJson(JsonBinding.java:93)
	at org.jboss.resteasy.plugins.providers.jsonb.JsonBindingProvider.readFrom(JsonBindingProvider.java:70)
	... 48 more

There must be a bug somewhere in Yasson, RESTEasy or Quarkus. The method execution works in wildfly but not in quarkus. Maybe yasson or something else cannot add a default constructor in quarkus at runtime if one is missing (by reflection).

Environment (please complete the following information):

• Output of java -version: 12
• Quarkus version or git rev: 1.0 Final

[geoand]

Can you please try using the resteasy-jackson dependency instead of resteasy-jsonb?

The json annotations that you are using seem to be Jackson annotations, not JSON-B annotations.

[nimo23]

just add a default constructor

@gsmet With default-constructor you mean a “no-arg-constructor”. I cannot add this - the class is within a library only included in my pom.xml. and secondly, such a class (with final fields) cannot have a no-arg-constructor.

The error:

Can't create instance of a class: class com.domain.Task, 
No default constructor found.
	at org.eclipse.yasson.internal.serializer.ObjectDeserializer.getInstance(ObjectDeserializer.java:95)
	at org.eclipse.yasson.internal.serializer.AbstractContainerDeserializer.deserialize(AbstractContainerDeserializer.java:61)

is misleading because quarkus uses falsely json-b instead of jackson and this is the reason why it is not working. The library which includes Task.class explicitly declares jackson and not json-b…however quarkus ignores this. Using @JsonCreator eliminates the need of an empty default constructor in jackson by definition. However, quarkus ignores this and wants a default constructor even if no such constructor is needed because the class uses @JsonCreator .

The error message is easy to understand

As I described above: the origin error which lead to this error is hard to trace and not shown in this error log because it is indirectly caused by the fact I described above.

So the only reason why this works in wildfly (even without adding a no-arg-constructor) is that it has a modular class loader (jboss modules). Am I right?