运行时Kryo序列化器IllegalAccessError

Question

We are trying to use Kryo Serializer to serialize our application object to push them in a kafka stream.

The serialization code has

   private ThreadLocal<Kryo> kryos = new ThreadLocal<Kryo>() {
        protected Kryo initialValue() {
            Kryo kryo = new Kryo();
            kryo.addDefaultSerializer(MyApp.class, new MyAppKyroSerializer());
            return kryo;
        };
    };

The serialize method is:

 @Override
    public byte[] serialize(String topic, MyApp data) {

        ByteBufferOutput output = new ByteBufferOutput(100);

        kryos.get().writeObject(output, data);
        return output.toBytes();
    }

While executing the Application we are getting the following IllegalAccessError:

Exception in thread "main" java.lang.IllegalAccessError: tried to access field com.esotericsoftware.kryo.io.Output.capacity from class com.esotericsoftware.kryo.io.ByteBufferOutput
    at com.esotericsoftware.kryo.io.ByteBufferOutput.<init>(ByteBufferOutput.java:66)
    at com.esotericsoftware.kryo.io.ByteBufferOutput.<init>(ByteBufferOutput.java:58)
    at com.mycom.serializer.MyAppSerializer.serialize(MyAppSerializer.java:43)

This is strange because ByteBufferOutput extends Output and capacity is a protected field.

Answer 1

public byte[] serialize(String topic, Myapp data) {

    Output output = new Output(100);
    kryos.get().writeObject(output, data);
    return output.toBytes();
}

Try this i think this will work..

Answer 2

As it said in Java Documentation for IllegalAccessError :

Normally, this error is caught by the compiler; this error can only occur at run time if the definition of a class has incompatibly changed.

So suggestion would be to check if all Kryo libs (in your project) are compliant with each other and belong to one-version of Kryo.