Setting up Java support

Perform the basic setup tasks to support Java™ in your CICS® region and configure a JVM server to run Java applications.

Before you begin

The Java components that are required for CICS are set up during the installation of the product. You must ensure that the Java components are installed correctly by using the information in Verifying your Java components installation.

About this task

CICS uses files in z/OS® UNIX to start the JVM. You must ensure that your CICS region is configured to use the correct zFS directories, and that those directories have the correct permissions. After you configure CICS and set up zFS, you can configure a JVM server to run Java applications.

Procedure

  1. Set the JVMPROFILEDIR system initialization parameter to a suitable directory in z/OS UNIX where you want to store the JVM profiles that are used by the CICS region.
    For more information, see Setting the location for the JVM profiles.
  2. Ensure that your CICS region has enough memory to run Java applications.
    For more information, see Setting the memory limits for Java.
  3. Give your CICS region permission to access the resources that are held in z/OS UNIX, including your JVM profiles, directories, and files that are required to create JVMs.
    For more information, see Giving CICS regions access to z/OS UNIX directories and files.
  4. Set up a JVM server.
    You can configure a JVM server to run different workloads. For more information, see Setting up a JVM server.
  5. Optional: Enable a Java security manager to protect a Java application from performing potentially unsafe actions.
    For more information, see Enabling a Java security manager.
  6. Set the JAVA_DUMP_TDUMP_PATTERN unformatted storage dump parameter.
    The dump is written to a sequential MVS data set, which can be changed by specifying a value for the environment variable JAVA_DUMP_TDUMP_PATTERN. Ensure that the CICS region user ID has UPDATE access to data sets matching this pattern, otherwise diagnostic data is lost. For more information, see Using dump agents on z/OS.

Results

You set up your CICS region to support Java and created a JVM server to run Java applications.

What to do next

If you are upgrading existing Java applications, follow the guidance in Upgrading. To start running Java applications in a JVM server, see Deploying applications to a JVM server.