What is message-driven bean in Java?

A message-driven bean is an enterprise bean that allows Java EE applications to process messages asynchronously. This type of bean normally acts as a JMS message listener, which is similar to an event listener but receives JMS messages instead of events.

What is message-driven bean explain in lifecycle?

Like a stateless session bean, a message-driven bean is never passivated, and it has only two states: nonexistent and ready to receive messages. At the end of the life cycle, the container calls the method annotated @PreDestroy , if any. The bean’s instance is then ready for garbage collection.

Why Kafka is so popular?

Kafka’s excellent performance makes it extremely popular. Kafka is fast and efficient, and with the right training, it’s easy to set up and use. One of Kafka’s main features is fault tolerant storage which makes it stable and reliable. It has a flexible publish-subscribe/queue that scales well.

What are characteristics of a message-driven bean?

MDBs have the following characteristics: They don’t have local or remote home and component interfaces. MDBs use lightweight, self-contained JMS messages to communicate asynchronously. Messages can be persistent or nonpersistent, and MDBs can provide guaranteed message delivery.

What are message driven beans give steps to create message driven beans?

Message driven bean is a stateless bean and is used to do task asynchronously. Step 1 − Create table in database (Refer to EJB-Persistence chapter). Step 2 − Create Entity class corresponding to table (Refer to EJB-Persistence chapter). Step 3 − Create DataSource and Persistence Unit (Refer to EJB-Persistence chapter).

What is the difference between message driven beans and stateless session beans?

The difference between stateless session beans and message-driven beans are: Message driven bean has only a bean class whereas stateless session bean can have an interface and a bean class. Clients cannot interact with message-driven bean directly, they can interact indirectly by sending messages to JMS Queue or Topic.

What is the purpose of message driven beans explain the various circumstances under which a message-driven bean should be used?

A message-driven bean is an enterprise bean that allows Java EE applications to process messages asynchronously. It normally acts as a JMS message listener, which is similar to an event listener except that it receives JMS messages instead of events.

What is Kafka message?

Apache Kafka is a publish-subscribe based durable messaging system. A messaging system sends messages between processes, applications, and servers. Apache Kafka is a software where topics can be defined (think of a topic as a category), applications can add, process and reprocess records.

What is the difference between session bean and entity bean?

There are two types of EJBs: session beans and entity beans. An easy way to think of the difference is that a session bean implements one or more business tasks, while an entity bean is a complex business entity. Your entity bean can manage multiple dependent persistent objects in performing its necessary tasks.

Which type of instances retain no data or conversational state for a specific client?

A message-driven bean’s instances retain no data or conversational state for a specific client.

What type of information must a bean expose for introspection purposes?

When Beans are used by a visual development tool, they have to expose their properties, methods, and events. This allows both the tool and the user to manipulate the Bean’s appearance and behavior.

What is Apache Kafka and how does it work?

From Wikipedia, the free encyclopedia Apache Kafka is a framework implementation of a software bus using stream-processing. It is an open-source software platform developed by the Apache Software Foundation written in Scala and Java. The project aims to provide a unified, high-throughput, low-latency platform for handling real-time data feeds.

What is Kafka consumer and producer in Java?

The consumer and producer APIs build on top of the Kafka messaging protocol and offer a reference implementation for Kafka consumer and producer clients in Java. The underlying messaging protocol is a binary protocol that developers can use to write their own consumer or producer clients in any programming language.

What happens to old data in Kafka?

If there are records that are older than the specified retention time or if the space bound is exceeded for a partition, Kafka is allowed to delete old data to free storage space. By default, topics are configured with a retention time of 7 days, but it’s also possible to store data indefinitely.

What are the different types of APIs in Kafka?

There are five major APIs in Kafka: Producer API – Permits an application to publish streams of records. Consumer API – Permits an application to subscribe to topics and processes streams of records. Connector API – Executes the reusable producer and consumer APIs that can link the topics to the existing applications.