Java in a TXSeries environment

TXSeries being positioned as a transaction processing platform for traditional applications written on COBOL, C, C++, and PL/I. - predominantly! There's no question asked if the entire application workload is written on Java which obviously would be hosted on a Java EE platform such as IBM WebSphere.

TXSeries and Java architecture

In TXSeries, CICS regions are designed to have a multi-process architecture model. That is, you will find a set of co-ordinated operating system processes running when you start a CICS region. There would be a number of application server processes running (1 to n, that are configurable), which are responsible to run the business transactions/applications. Each of this application server process would then have the JVM initialized, when a Java application is run on it. The classes gets loaded within the JVM heap of the application server process and are not shared with other application server processes.

Running Java programs on TXSeries would suffer performance impacts due to its architecture; nevertheless the Java support on TXSeries has certain advantages like below:

• To invoke a web service
• To integrate with external Java applications
• Access CICS services using JCICS API

To invoke a Java CICS program, you don't need a special semantics... you can just do a EXEC CICS LINK command to call the Java/CICS program. TXSeries takes care of the data conversion between Unicode and your language code page.

There are certain limitations in using the Java support, like for example, you can't deploy an EJB on TXSeries, and only limited set of JCICS API (v1) are supported for TXSeries.

You can use Rational Application Developer (RAD) tooling for developing TXSeries/Java applications.

For more information on the Java support on TXSeries refer to the following:

TXSeries Redbooks:
http://www.redbooks.ibm.com/abstracts/sg247185.html (section 3.6.1. details programming in Java)

TXSeries IEA Website material:
http://publib.boulder.ibm.com/infocenter/ieduasst/v1r1m0/topic/com.ibm.iea.txseries/txseries/6.1/Programming/TXSeriesV6_JAVA/player.html?dmuid=20061231124436896636