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IBM continues its tradition of Java™ support on z/OS, while exploiting IBM Z hardware features that are designed to deliver better performance and capabilities for your Java applications.
Required level of Java for z/OS
z/OS 3.2 and z/OS 3.1 are designed for use with IBM Semeru Runtime Certified Edition for z/OS 25 for z/OS provided functions. The Semeru 25 software development kit (SDK) supports the Java™ Standard Edition 25 language specification, which enables Java 25-compliant applications to be ported to and deployed on z/OS.
While z/OS 3.2 and z/OS 3.1 support Java 21 and earlier Java levels for your applications and will continue to do so over their lifecycles, these z/OS release are designed for Java 25 and later. New or enhanced functions in z/OS might require Java 25, and additional product support is planned to be delivered over time through service refreshes. Functions that are unchanged from previous z/OS releases should work with earlier supported versions of the IBM SDK (Java Technology Edition).
For z/OS orders, IBM Semeru Runtime Certified Edition for z/OS 25 is available as a bypassable requisite when you order z/OS through Shopz (as product 5655-JB2). For the specific Java dependencies for affected z/OS components and elements, see the table that follows. The Java dependencies must be followed for proper functioning of z/OS.
To use Semeru 25 for z/OS functions, you must ensure that the JAVA_HOME environment variable for your system references the correct Java runtime. By default, the SDK resides in the following directory on your system: /usr/lpp/java/J25.0_64. If you installed the SDK in another location, be sure to update the JAVA_HOME location for the z/OS functions that use Java. For more information, see the z/OS product publications for the functions used and the location for specifying the JAVA_HOME environment variable.
z/OS provides support for Java in the form of program temporary fixes (PTFs). To identify the PTFs for Semeru 25 use the following SMP/E fix category: IBM.TargetSystem-RequiredService.Semeru.25
If you have applications that depend on Java, you must ensure that the proper Semeru level is provided. Do not forget to accommodate any Semeru upgrade actions that those levels might entail if you upgrade from a prior Semeru release for your applications.
For related information, see IBM software announcement AD26-0015.
z/OS elements and components that use Java
For the specific Java dependencies for affected z/OS elements and components, and the Java home location, see the table that follows. The Java dependencies must be followed for proper functioning of z/OS.
| z/OS element or feature | Required level of Java | Java home location |
|---|---|---|
| Base Control Program (BCP) | These BCP components require IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2). |
|
| Capacity Provisioning Manager (CPM) | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | Java home is set through the configuration file /etc/zexpl/zee.env |
| DFSMS | The DFSMS Object Access Method (OAM) feature requires IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2). | Not applicable. The ldapdiff utility uses Java, but the script that runs the utility does not specify a Java home. Rather, the script inherits the Java virtual machine (JVM) characteristics from the calling program. |
| IBM Tivoli Directory Server | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | Java home is set in the user profile or system profile. |
| IBM z/OS Liberty Embedded | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | Java home is set by the STDENV DD statement in the started task procedure. Or, it is set in the server environment variables file server.env |
| IBM z/OS Management Facility (z/OSMF) | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | Java home is set through the JAVA_HOME parameter in the IZUPRMxx parmlib member. Consider using a system symbol for the Java directory. For example, if your installation defines a symbol in IEASYMxx for the Java directory /usr/lpp/java/J25.0_64, you can reference this directory through a symbol specified on the JAVA_HOME parameter in IZUPRMxx, as follows:JAVA_HOME(&JAVA25) |
| Infoprint Server | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | For Infoprint Central, Java home is set in the environment variables file for the HTTP server: ../bin/envvarsNote: With the installation of the PTF for APAR OA67298, Java support is no longer required for the Internet Printing Protocol (IPP) function of Infoprint Server (AOPIPPD). |
| PKI Services | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | If your installation has configured PKI Services to use JSP and XML to implement its web application for certificate management, access to the Java SDK is established through z/OS WebSphere Liberty server. The JAVA_HOME setting resides in the server environment file (server.env). PKI Services also includes a shell script that invokes a Java program that uses the Java found in the PATH environment variable. Or, if not found in PATH, the program uses ${JAVA_HOME}/bin/java.If PKI Services is configured to use REXX .CGI files with IBM HTTP Server (IHS) to implement its web application for certificate management, Java is not used. |
| SDSF | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | Not applicable. The SDSF API inherits the Java virtual machine (JVM) characteristics from the calling program. |
| SMP/E | IBM Semeru Runtime Certified Edition for z/OS 25 (5655-JB2) | Java home is specified in the SMPCLNT data set. |
Upgrading from Semeru 21 and earlier releases
Although Java 21 and earlier releases (while still in service) are supported on z/OS 3.2 and z/OS 3.1 for your own applications, you should expect that certain z/OS system-provided Java facilities will require IBM Semeru 25.
For your applications, z/OS 3.2 and z/OS 3.1 also support the use of Java 17, 11, and 8 and will continue to do so over the lifecycles for these Java releases. Specifically, your applications can continue to use the following levels of the IBM SDK, while these levels are still supported:
- IBM Semeru Runtime Certified Edition for z/OS, Version 21 (5655-JB1)
- IBM Semeru Runtime Certified Edition for z/OS, Version 17 (5655-UA1)
- IBM Semeru Runtime Certified Edition for z/OS, Version 11 (5655-DGJ)
- IBM 64-bit SDK for z/OS, Java Technology Edition, V8 (5655-DGH)
- IBM 31-bit SDK for z/OS, Java Technology Edition, V8 (5655-DGG)
- IBM Semeru Runtime Certified Edition for z/OS, Version 17 (5655-UA1)
- IBM Semeru Runtime Certified Edition for z/OS, Version 11 (5655-DGJ)
- IBM 64-bit SDK for z/OS, Java Technology Edition, V8 (5655-DGH)
- IBM 31-bit SDK for z/OS, Java Technology Edition, V8 (5655-DGG)
z/OS provides support for Java in the form of program temporary fixes (PTFs). To identify the PTFs for Semeru 21, use the following SMP/E fix category (FIXCAT): IBM.TargetSystem-RequiredService.Semeru.*
If you are upgrading from an earlier Java release to Version 25 for your own applications, follow the Semeru migration actions found in Migrating from earlier releases of IBM Semeru Certified Edition for z/OS.
What's new
7 April 2026
Added information for IBM Semeru Runtime Certified Edition for z/OS 25 for z/OS.
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Modified date:
08 April 2026
UID
ibm17240923