Both of them might look alike, but they are quite different.
For example, Nested transactions can operate concurrently, where as the "REQUIRES NEW" stuff will make the callee to wait until the spawned transaction returns back!
EJB Spec (page no. 332) makes clear why nested transactions are not supported.
Note: The decision not to support nested transactions allows vendors of existing transaction processing and database management systems to incorporate support for Enterprise Java- Beans. If these vendors provide support for nested transactions in the future, Enterprise Java- Beans may be enhanced to take advantage of nested transactions.
Well, I took about 40 days for the full preparation. I started with Mastering EJB book. Then I printed out EJB spec and bought HFEJB book. I read them parallely. Once I am done with HFEJB, I was reading only EJB spec
Once I became confident of the EJB conepts, I took the mock exam in HFEJB book. The next day I took EJBCertificate.com mock exam. 2 days after that, I gave SCBCD exam.
Bala<br />SCJP 1.4 98%<br />SCBCD 1.3 -- 88%
Yeah, but how did the squirrel get in there? Was it because of the tiny ad?
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop