This chapter gives a brief description of Java and the Java Native Interface (JNI) and explains why you might be interested in using it with PL/I. A simple Java - PL/I application will be described and information on compatibility between the two languages will also be discussed. Instructions on how to build and run the Java - PL/I sample applications assume the work is being done in the z/OS UNIX System Services environment of z/OS.
Before you can communicate with Java from PL/I you need to have Java installed on your z/OS system. Contact your local System Administrator for more information on how to set up your z/OS Java environment.
These sample programs have been compiled and tested with Java 2 Version 1.4.2. To determine the level of Java in your z/OS UNIX System Services environment enter this command from the command line:
java -version
The active Java version will then be displayed and will look something like:
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2) Classic VM (build 1.4.2, J2RE 1.4.2 IBM z/OS Persistent Reusable VM build cm142