ClassCastException while converting LinkedHashMap to generic class

Question

Consider the following class :

public class MsgReceiver<MSG> extends AbstractMsgReceiver<MSG> implements 
MsgReceiver<MSG> {

@KafkaListener( // necessary properties )
public void receiveMessage(@Headers Map<String, Object> headers, @Payload ConsumerRecord<String, 
Object> payload) {

    super.receiveMessage(headers,(MSG) (payload.value())); // line foobar
}

The payload.value() is of type LinkedHashMap and when I use this class, MSG can be any of my custom POJO class. I get ClassCastException when converting from LinkedMashMap to my POJO class on line foobar. How can I resolve this ?

I do not expect that to work, I tried to use ObjectMapper but even that throws error. — definepi314, Aug 02 '20 at 16:46
What does ObjectMapper have to do with this? You have a List with entries. You cannot cast a List to some POJO. What are the List's elements? — f1sh, Aug 02 '20 at 16:48

score 0 · Answer 1 · answered Aug 02 '20 at 16:50

0

Try using jackson mapper, or any mapper I'd say. I have been using jackson mapper for kafka queue listeners, works perfectly Find details here

answered Aug 02 '20 at 16:50

Michael

76
5

score 0 · Answer 2 · answered Aug 02 '20 at 17:52

0

payload.value() returns iterator object. It might be the issue in typecasting. Check your POJO class for it.

answered Aug 02 '20 at 17:52

PRADEEP CHOUDHARY

46
5

ClassCastException while converting LinkedHashMap to generic class

2 Answers2