Exception while dispatching incoming RPC call com.google.gwt.user.client.rpc.SerializationException: Type 'com.google.gson.internal.LinkedTreeMap' was not assignable to 'com.google.gwt.user.client.rpc.IsSerializable' and did not have a custom field

[Ashi Dev]

Exception while dispatching incoming RPC call

com.google.gwt.user.client.rpc.SerializationException: Type 'com.google.gson.internal.LinkedTreeMap' was not assignable to

 'com.google.gwt.user.client.rpc.IsSerializable' and did not have a custom field serializer.For security purposes, this type will not be serialized.: 

 instance = {}

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:696) ~[gwt-servlet.jar:na]

Using GWT 2.8.2, Java 11, compliance level 1.8,  gson.jar version 2.8.6  On linux.

However, on windows same set up works with gson jar 2.2.2 but not with 2.8.6.

Can you help?

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[José Reis]

Try using jdk, jre directly 1.8. Some of my issues disapeared after I switch from java13 to java8.