Lambda serialization problem

[andre-paris]

I'm using Kryo for serialization inside Hazelcast.
The lambda is sent like this:

Hazelcast.newHazelcastInstance()
                .getExecutorService("exec")
                .executeOnKeyOwner(() -> {
                    // some code on Runnable.run()
                });

Serializer read this way:

public Object read(ObjectDataInput in) throws IOException {
    Kryo kryo = new Kryo();
    kryo.register(SerializedLambda.class);
    kryo.register(Closure.class, new ClosureSerializer());

    Input input = new Input((InputStream) in);

    return kryo.readClassAndObject(input);
}

I got this error:

Caused by: java.lang.RuntimeException: Could not serialize lambda
    at com.esotericsoftware.kryo.serializers.ClosureSerializer.write(ClosureSerializer.java:67) ~[kryo-4.0.0.jar:na]
    at com.esotericsoftware.kryo.Kryo.writeClassAndObject(Kryo.java:651) ~[kryo-4.0.0.jar:na]
    at com.paris.sandbox.HazelcastConfig$KryoSerializer.write(HazelcastConfig.java:94) ~[classes/:na]
    at com.hazelcast.internal.serialization.impl.StreamSerializerAdapter.write(StreamSerializerAdapter.java:41) ~[hazelcast-3.7.2.jar:3.7.2]
    at com.hazelcast.internal.serialization.impl.AbstractSerializationService.writeObject(AbstractSerializationService.java:199) ~[hazelcast-3.7.2.jar:3.7.2]
    ... 77 common frames omitted
Caused by: java.lang.NoSuchMethodException: com.paris.sandbox.HazelcastRest$$Lambda$17/70747700.writeReplace()
    at java.lang.Class.getDeclaredMethod(Class.java:2130) ~[na:1.8.0_91]
    at com.esotericsoftware.kryo.serializers.ClosureSerializer.write(ClosureSerializer.java:58) ~[kryo-4.0.0.jar:na]
    ... 81 common frames omitted

I'm missing something?

Thanks

[jerrinot]

Hi @andre-paris,

I believe Kryo requires lambdas to be marked as Serializable. Can you try to change it to

Hazelcast.newHazelcastInstance()
                .getExecutorService("exec")
                .executeOnKeyOwner((Runnable & Serializable) () -> { // <--- instruct lambda factory to create serializable lambdas
                    // some code on Runnable.run()
                }, "key");

It will use Kryo, but the the regular Java serialization. Marking it as (Java) serializable is necessary as otherwise generated lambda classes won't have all necessary methods.

[magro]

@jerrinot thanks for stepping in! I assume this resolved the issue for @andre-paris.