Essential JBoss Interview Questions & Answers:

1. Can I unit test Seam applications without starting the Application Server?

Yes, Seam provides its own integration test framework based on TestNG. You can easily mock all Seam services using those facilities without ever loading an application server or a database. Refer to the testexample ANT target in the Seam booking example application for more details.

2. Can I use AJAX with Seam?

A: Yes, Seam provides excellent support for AJAX. First, Seam supports the ICEfaces and Ajax4JSF Ajax component libraries for JSF. If you prefer a more "old fashioned" approach, Seam provides a complete JavaScript remoting framework which lets you call Seam components and subscribe to JMS topics directly from the client. Please refer to the Seam remoting example application on how to use AJAX remoting to implement a chat room.

3. Is it true that Seam only works with JSF?

Seam only supports JSF as a view framework at this time. We plan to support other web frameworks in the future. We like JSF because it is a component-based UI framework, which fits really well with Seam's component-based approach to business objects and persistence objects. Seam made a major improvement to JSF by eliminating almost all XML configuration for backing beans -- you can now define back beans from POJOs or EJB3 components using simple annotations. We recommend you use Facelets, instead of JSP, with JSF. Facelets provide a powerful templating framework, better appplication performance, and allows us to write much simpler JSF pages. Please see the Seam booking example application for an example on how to use Facelets.

4. Where can I find Seam examples and documentation?

The source code and build script of all Seam example applications are included in the examples directory of the Seam distribution.

5. Can I run Seam with JDK 1.4 and earlier?

No, Seam only works on JDK 5.0 and above. It uses annotations and other JDK 5.0 features.

6. Can I run Seam in a J2EE environment?

Yes, as of Seam 1.1, you can use Seam in any J2EE application server, with one caveat: you will not be able to use EJB 3.0 session beans. However, you can use either Hibernate or JPA for persistence, and you can use Seam JavaBean components instead of session beans.

7. Can I run Seam outside of JBoss AS?

Yes, you can run Seam applications in plain Tomcat 5.5+ or in the Sun GlassFish application server. To run Seam application in Tomcat, you need a number of additional library files and a few configuration files to bootstrap the JBoss EJB3 inside Tomcat. Please refer to the deploy.tomcat ANT build target for the Seam booking example (in the examples/booking directory of the Seam distribution) for more on how to build a Tomcat WAR for Seam applications. Refer to this blog post on how to run Seam in Sun's Glassfish application server.

8. 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.

9. Do you know how you could add support for Web Service transactions?

JBossTS supports Web Services transactions, including extended transaction models designed specifically for loosely-coupled, long running business processes. J2EE transactions can integrate seamlessly with Web Services transactions using our integrated, bi-directional transaction bridge. Interoperability with many other vendors is provided out-of-the-box and JBoss is an active participant in these standards.

10. What is the difference between JAX--WS and JAX-RPC?

Java API for XML-Based RPC (JAX-RPC) is a Legacy Web Services Java API, it uses SOAP and HTTP to do RPCs over the network and enables building of Web services and Web applications based on the SOAP 1.1 specification, Java SE 1.4 or lower.JAX-WS 2.0 is the successor to JAX-RPC 1.1. JAX-WS still supports SOAP 1.1 over HTTP 1.1, so interoperability will not be affected. However there are lots of differences:

► JAX-WS maps to Java 5.0 and relies on many of the features new in Java 5.0 like Web Service annotations.
► JAX-RPC has its own data mapping model, JAX-WS's data mapping model is JAXB. JAXB promises mappings for all XML schemas.
► JAX-WS introduces message-oriented functionality, dynamic asynchronous functionality which are missing in JAX-RPC.
► JAX-WS also add support, via JAXB, for MTOM, the new attachment specification.