Your topic is log compacted and you are sending a message with the key K and value null .
What will happen?
A . The broker will delete all messages with the key K upon cleanup
B . The producer will throw a Runtime exception
C . The broker will delete the message with the key K and null value only upon cleanup
D . The message will get ignored by the Kafka broker
Sending a message with the null value is called a tombstone in Kafka and will ensure the log compacted topic does not contain any messages with the key K upon compaction