21.Explain with an example the implementation of source queue for MDB?

The implementation of the source queue for MDB is used to be the container specific file that consists of information regarding the queue like queue name for MDB that resides in jboss.xml and the source file that is used with it remains in the queue till the message is not being transferred by the server. The server executes the file and keeps a log file to maintain all the information. The modification can be done by using the source queue. If any additional information, be required using the source queue then message driven beans allow the use of extra parameters like destination, name, etc. to describe the objects. The code is shown below:
<jboss>
<enterprise-beans>
<message-driven>
<ejb-name>SimpleMessageBean</ejb-name>
<destination-jndi-name>queue/MyQueue</destination-jndi-name>

22.What are needed to set-up a cluster with JBoss ?

Basically starting JBoss with the \'all\' configuration contains everything needed for clustering:
It has all the libraries for clustering:
JGroups.jar, jboss-cache.jar
Clustered beans (cluster-service.xml)
HA-JNDI
HTTP session replications (tc5-cluster-service.xml)
Farming
HA-JMS

23.Which component handles cluster communication in JBoss?

The JGroups framework provides services to enable peer-to-peer communications between nodes in a cluster. It is built on top a stack of network communication protocols that provide transport, discovery, reliability and failure detection, and cluster membership management services.

24.Is it possible to put a JBoss server instance into multiple cluster at the same time ?

It is technically possible to put a JBoss server instance into multiple clusters at the same time, this practice is generally not recommended, as it increases the management complexity.

25.What\'s JBoss cache in short?

JBossCache enables easy distribution of datasets across your computing environments. It is based on JGroups and enables clustering and high availability of that data. You may choose to distribute the data with JBoss Messaging to move it where it is needed for computation or event-based programming.

26.What is about Seam?

Built on the standards JavaServer Faces and EJB 3.0, JBoss Seam unifies component and programming models and delivers a consistent and powerful framework for rapid creation of web applications with Java EE 5.0. Seam simplifies web application development and enables new functionality that was difficult to implement by hand before, such as stateful conversations, multi-window operation, and handling concurrent fine-grained AJAX requests.
Seam also unifies and integrates popular open source technologies like Facelets, Hibernate, iText, and Lucene.

27.Does Seam run on other application servers besides JBoss?

Seam runs beautifully on other application servers - just like everything else the Hibernate team does, this is not a JBoss-only thing.

28.What\'s JBoss JBPM?

JBoss JBPM is a platform for process languages. At the base there is a java library to define and execute graphs. The actual process constructs like e.g. send email, user task and update database are defined on top of this. Every process language is made up of a set of such process constructs. And that is what is pluggable in this base library. On top of the JBoss jBPM base library, there are implemented several process languages as a set of process constructs: jPDL, BPEL and SEAM pageflow:
jPDL is a process language with a clean interface to Java and very sophisticated task management capabilities. There is no standard for Java process languages, so it is proprietary.
BPEL is a service orchestration language. As said before, in BPEL, you can write new services as a function of other services. This is typically a component of an Enterprise Service Bus (ESB).
SEAM pageflow is a language that allows for the graphically define the navigation between pages in a SEAM web application. Is it helpful? Yes No Add Comment View Comments

29.How do you monitor JBoss and detect the bottleneck of an application?

The first step is to measure the different components of your app to see where the degradation is. Is it an external resource (database, message server, etc.)? Is it internal? Where is the app spending all its time? So the first step could be to to use JBoss JMX agents and monitor the components deployed to the application server. Once it\'s clear which component or library takes most of the time or most of resource you can use a more specialized tool like JProbe and examine the single method or the single objects loaded in memory.

30.What is JBoss?

JBoss is a popular open source application server based on Java EE technology. Being Java EE based, the JBoss supports cross-platform java applications. It was embedded with Apache Tomcat web server. It runs under any JVM of 1.3 or later versions. JBoss supports JNDI, Servlet/JSP (Tomcat or Jetty), EJB, JTS/JTA, JCA, JMS, Clustering (JavaGroups), Web Services (Axis), and IIOP integration (JacORB).

31.. What version of JBoss AS do I need to run Seam?

For Seam 1.3: Seam was developed against JBoss 4.2. Seam can still be run against JBoss 4.0. The seam documentation contains instructions for configuring JBoss 4.0.
For Seam 1.2: Since Seam requires the latest edition of EJB3, you need to install JBoss AS from the latest JEMS installer. Make sure that you select the “ejb3″ or “ejb3+clustering” profile to include EJB3 support. Also, the jboss-seam.jar library file from the Seam distribution must be included in each Seam application you deploy. Refer to examples in Seam distribution (inside the examples directory) to see how to build and package Seam applications.

32.What is JBoss cache ?

JBoss cache is a product. Frequently accessed Java objects are cached by utilzing JBoss cache to improve the performance of e-business applications. JBoss decreases the network traffic and increases the scalability of applications by eliminating unnecessary database acces.Fully transactional features and highly configurable set of options which are to deal with concurrent data access, are provided by JBoss cache in an efficient manner possible for the applications.

33.What is the difference between Hibernate and EJB 3? Do not you think EJB 3 is just a clone of Hibernate?

The perception of EJB3 as being a simple clone of Hibernate is primarily based on developer familiarity with Hibernate and a similarity of naming, as well as common purpose, and that Hibernate is morphing itself into an EJB3 implementation based on the work going into the specification, not the other way around.
EJBs are supposed to be components, in the sense that they're not just one class, but a set of classes, descriptors and usage and management contracts. All of this in order to allow a container (JBoss, Weblogic, etc.) to provide services to those components, and to be able to reuse and distribute this components. This services are, among others, transactions, concurrent access control, security, instance pooling, etcetera.
Hibernat is "just" an ORM (Object/Relational Mapping) tool. Quick and dirty, this means you can store an object tree belonging to an class hierarchy in a relational DB without writing a single SQL query. Quite cool, IMO. But no transaction control, no instance pooling, no concurrency control, and certainly no security.

34.Which Hibernate object wraps the JDBC Connection?

The Session interface wraps a JDBC Connection. This interface is a single threaded object which represents a single unit of work with application and persistent database. It's retrieved by the SessionFactory's openSession() method

35.Is the Session Factory Thread safe?

Yes: that is many threads can access it cuncurrentely and request for sessions. It holds cached data that has been read in one unit of work and may be reused in a future unit of work. Good practice is to create it when the application is initialized.

36.How can you start a JTA transaction from a Servlet deployed on JBoss?

JBoss registers in the JNDI tree a JTA UserTransaction Object which can be user to manage a distributed transaction.

37.What if you need to span your transaction across multiple Servlet invocations?

You can't with a Servlet. A JTA transaction must start and finish within a single invocation (of the service() method). You should consider using a Stateful SB. In a SFSB with a JTA transaction, the association between the bean instance and the transaction is retained across multiple client calls.

38.What are the differences between EJB 3.0 and EJB 2.0?

EJBs are now plain old Java objects (POJO) that expose regular business interfaces (POJI), and there is no requirement for home interfaces.►Use of metadata annotations, an extensible, metadata-driven, attribute-oriented framework that is used to generate Java code or XML deployment descriptors.► Removal of the requirement for specific interfaces and deployment descriptors (deployment descriptor information can be replaced by annotations).►Interceptor facility to invoke user methods at the invocation of business methods or at life cycle events.► Default values are used whenever possible (“configuration by exception” approach).►Reduction in the requirements for usage of checked exception.► A complete new persistence model (based on the JPA standard), that supersedes EJB 2.x entity beans

39.What is the diffrence between a local-tx-datasource and a xa-datasource? can you use transactions in both?

A local-tx-datasource identifies a data source that uses transactions, even distributed trans actions within the local application server, but doesn’t use distributed transactions among multiple application servers. An xa-datasource on the other hand identifies a data source that uses distributed transaction among multi-ple application servers.

40.What do you need to set-up a cluster with JBoss?

Basically starting JBoss with the “all” configuration contains everything needed for clustering: It has all the libraries for clustering:►JGroups.jar, jboss-cache.jar►Clustered beans (cluster-service.xml)►HA-JNDI►HTTP session replications (tc5-cluster-service.xml)►Farming► HA-JMS