msgpack_err.java

    @Message
    public static class MsgHeader {
        public MsgHeader() {
            msgId = -1;
        }

        @Index(0)
        public int msgId;

        public byte[] toBytes() {
            try {
                MessagePack msgpack = new MessagePack();
                return msgpack.write(this);
            } catch (IOException ex) {
                ex.printStackTrace();
                return null;
            }
        }
        public MsgHeader fromBytes(byte[] bytes) {
            MsgHeader header = null;
            try {
                MessagePack msgPack = new MessagePack();
                header = msgPack.read(bytes, MsgHeader.class);
                switch (header.msgId) {
                    case EFAML_CALL_CANCEL:
                        return msgPack.read(bytes, ClientCall.class);
                }
            } catch (Exception e) {

            }
            return null;
        }
    }
    
@Message //
public static class ClientCall extends MsgpackMsg.MsgHeader {
    public ClientCall() {
        msgId = MsgpackMsg.EFAML_CALL_CANCEL;
    }

    @Index(1)
    public int time = 0;
    @Index(2)
    public String url;
  
}

//and this is invoked from native layer
public void test(byte[]bytes){
   MsgpackMsg.MsgHeader msgHeader = new MsgpackMsg.MsgHeader().fromBytes(bytes);
   if (msgHeader == null)
      return;
    int msgPackId = msgHeader.msgId;
    try {
        handle(msgPackId, msgHeader);
    } catch (Exception e) {
        Log.ex(e.toString());
    }
}