CODEWITHSUNDEEP
javajakarta-ee
Dog
Dog

Reputation: 7787

Trouble understanding the opening page of Java EE 7 Developer Handbook

In the section "Java EE 7 architecture" (page 11) of Java EE 7 Developer Handbook, it says (emphasis mine):

Java EE architecture can be thought of as four separate containers. The first one is called the EJB container for lifecycle management of Enterprise Java Beans and the second container is the web container for lifecycle management of Java Servlets and managed beans. The third container is called the Application Client container, which manages the lifecycle of the client-side components. Finally, the fourth container is reserved for Java Applets and their lifecycle.

[something about jars]

A fully conformant Java EE product, such as Glassfish or JBoss Application Server has both containers.

Which containers is it referring to when it says "both containers"? Are these the same set of four containers mentioned in the above paragraph?

Less importantly, the paragraph before all this ends with:

For a beginner, reading this section is frankly essential.

What does it mean by "frankly"?

Upvotes: 0

Views: 236

Answers (1)

peter_pilgrim
peter_pilgrim

Reputation: 1160

I am Peter A. Pilgrim, the author of the Java EE 7 Developer Handbook. GlassFish and Java EE 7 application servers generally have at least two containers in the running configuration: EJB and Web. There is a third container for CDI.

For beginners, I appreciate this is very confusing and comes down to the history of Java EE (J2EE) and the Java web JSRs [standards] in the last 10-15 years. Generally, if you want to use EJB then you need an application server that has an EJB container, if you want to use Java Servlets, JSP, JSF, JAX-RS, and Java WebSocket then you may need an application server that has a Servlet container and if you want to use CDI (Context and Dependency Injection) beans then you need an application server that has a CDI container.

Lucky there are open source servers available for Java EE 6 and Java EE 7. The other greats news in 2013 is that you will start to have more Java EE 7 choices. GlassFish 4 is the reference implementation for Java EE 7, but it is closely followed by JBoss Wildfly and in the medium term Tomitribe's TomEE server has pledged to support Java EE 7.

If you discover any errata in the book, then can you please submit it to Packt Pub.

HTH

Upvotes: 1

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