We are planning to use a COBOL Stored procedure called from an J2EE application to perform updates into DB2 Db in mainframe. DB2 Stored procedures which run under the WLM, are they part of the J2EE container Transaction or not? My concern is that when the stored procedure complets and returns back to the Java code, are the updates committed at that point?
Yes. The transaction-logic is controlled by the java-client (in your case the J2EE container). This is normal behaviour and can be overrulled if you wish.
Look at this (slide 14) http://www.mdug.org/f13.ppt