Spring

Question 1

What are spring beans?

Answer 1

Usually, Spring Beans are Java objects which are managed by the Spring container.

Question 2

why do auditing with hibernate envers

Answer 2

Envers is a mature auditing module provided by Hibernate. It is highly configurable and lacks the flaws of the pure JPA implementation. Thus, it allows us to audit the delete operation, as it logs into tables other than the entity's table.
The Spring Data JPA approach abstracts working with JPA callbacks and provides handy annotations for auditing properties. It's also ready for integration with Spring Security. The disadvantage is that it inherits the same flaws of the JPA approach, so the delete operation cannot be audited.

Question 3

How does Spring AMQP work

Answer 3

While using messaging frameworks like rabbitmq where we sends messages across services, by default spring amqp re-queue’s any messages that haven’t been processed

This process can go on forever. Instead we can set re-queue as false at listener level or throw a exception

In order to better handle these failed messages we have the dead letter q approach

Question 4

What are dead letter Q

Answer 4

A Dead Letter Queue (DLQ) is a queue that holds undelivered or failed messages. A DLQ allows us to handle faulty or bad messages, monitor failure patterns and recover from exceptions in a system.