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I have a scenario where I have to save the JMS messages on disk. I write the messages in JSON format using the Gson library as follows:

Gson gson = new Gson();
String json = gson.toJson(message);
bufferedWriter.write(json);

But when I try to read this message,

Message m = gson.fromJson(json, Message.class);
System.out.println(m.getJMSType());

I get an exception:

java.lang.RuntimeException: Unable to invoke no-args constructor for interface javax.jms.Message. Register an InstanceCreator with Gson for this type may fix this problem.
    at com.google.gson.internal.ConstructorConstructor$12.construct(ConstructorConstructor.java:210)
    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:207)
    at com.google.gson.Gson.fromJson(Gson.java:814)
    at com.google.gson.Gson.fromJson(Gson.java:779)
    at com.google.gson.Gson.fromJson(Gson.java:728)
    at com.google.gson.Gson.fromJson(Gson.java:700)

How do I read a JMS message from Json string?

trailblazer
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1 Answers1

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Message is an interface. Gson can't initialize it. If the actual implementation class is known/under your control - you may replace deserialization with something like 

Message m = gson.fromJson(json, ActiveMQBlobMessage.class);

Otherwise, if you need interface - you may look at this post.

Community
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Peter Alexeev
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