Chuck Stephanski

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since Aug 25, 2010
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Recent posts by Chuck Stephanski

EclipseLink provides the reference implementation of SDO and this is a good place to start
http://wiki.eclipse.org/EclipseLink/FAQ/WhatIsSDO
9 years ago
supertype = parent type
subtype = child type

the sub type is MORE restrictive, correct?

Integer is a subtype of Number and Integer is more restrictive. You can assign an Integer to a Number, but you cannot assign a Number to an Integer.

Likewise, you can assign a List<Integer> to a List<? super Integer> but you cannot assign a List<Integer> to a List<? super Number>. The more restrictive type is the subtype.
10 years ago
I've played w/ Glassfish v3 a bit and done a lot of reading. I'm excited. JEE6 looks really strong for end to end java web development - from backend storage to presentation.
A Java Application Server such as Glassfish, JBoss, Weblogic, etc is a complete implementation of all of the Java EE specifications, of which EJB is one. As such, app servers lay down a large number of jar files on your disk when you install them. Most java IDE's have a project wizard that asks you what technologies your project will include when you set it up. They use this to copy the appropriate jars to your class path.

Note that most (perhaps all) of the Java EE API's have standalone implementations. So for example, OpenEJB is a standalone implementation of EJB that allows one to develop against the EJB API w/o installing an application server.

IMO Ben, I would not invest in learning EJB. I would learn the Java EE 6 stack, with a focus on JPA, JSF and CDI. EJB has a de-emphasized role in JEE5, and a further de-emphasized role in JEE6.
When you install a Java EE Application Server such as Glass Fish, implementations of all the Java EE API's are installed. EJB is a JEE API, so with Glass Fish installed you have EJB.