J.J. Beam questions

• What if a Kafka's consumer handles a message too long? Will Kafka reappoint this partition to another consumer and the message will doubly handled?
• How can I combine @DataJpaTest @SpringBootTest in one MVC application for testing every layer?
• Java 8 Map merge VS compute, essential difference?
• Why is the finalize() method deprecated in Java 9?
• Java IntStream iterate vs generate when to use what?
• How does Kafka guarantee consumers doesn't read a single message twice?

J.J. Beam answers