Java J2ee Planet

A Java Bean is defined as an instance of a class that contains private attributes (data), and getter & setter methods. If you have: private String myString; in your class, you should have the methods public String getMyString (); and public void setMyString (String settingString); defined in your code. Although, I have found that it is not absolutely nessary to have everything defined; just don't be surprised if something breaks! An EJB (Enterprise Java Bean) is much more complex They only reside in application servers that handle EJBs (Tomcat doesn't hold EJBs). There are 3 types of EJBs: 1) Session Usually contain some business logic. 2) Entity Usually interface with a data store (such as a database). 3) Message-Driven Receives messages from JMS

1. What is JMS ? A. JMS (JAVA MESSAGING SERVICE) is an API .It is a specification with one package javax.jms .It is a technology which can pass the information synchronously or asynchronously . 2. On what technology is JMS based ? A. JMS is based on Message-Oriented MiddleWare (MOM). 3. What was the technology for messaging services before JMS was released? A. Before JMS API specification was released by javasoft ,there was IBM’s MQSeries implementation of MOM (Message-Oriented MiddleWare). 4. What is MOM (Message-Oriented MiddleWare) ? A. MOM is a software infrastructure that asynchronously connects multiple system’s through the production and consumption of data message. 5. How many types of data passing does JMS specification allows ?What are they? A. JMS specification allows two types of data passing. a)publish/subscribe [pub/sub model] b)point-to-point [p-t-p model] 6. In real time which type of data passing is used ? A. Mostly in real time applications we use both type...

Message-Oriented-Middleware provide a common reliable way for programs to create, send, receive and read messages in any distributed Enterprise System. MOM ensures fast, reliable asynchronous electronic communication, guaranteed message delivery, receipt notification and transaction control. The Java Message Service (JMS) provides a standard Java-based interface to the message services of a MOM of some other provider. Messaging systems are classified into different models that determine which client receives a message. The most common messaging models are: Publish-Subscribe Messaging Point-To-Point Messaging Request-Reply Messaging Not all MOM providers support all these models. Publish-Subscribe Messaging When multiple applications need to receive the same messages, Publish-Subscribe Messaging is used. The central concept in a Publish-Subscribe messaging system is the Topic. Multiple Publishers may send messages to a Topic, and all Subscribers to that Topic receive all the messages s...