Considerations for Java V5 and V6

Before Java V5 and V6 programs can be sampled, the J9VM support in Application Performance Analyzer must be enabled. Contact your systems programmer to verify this support is enabled.

Only one observation at a time is supported for a specific Java V5 or V6 address space.

IMS Java V5 and V6 programs are not supported.

CICS Java programs are supported for CICS/TS 4.2 and above.

Application Performance Analyzer will stop sampling Java V5 and V6 programs when the main thread ends, even if the specified number of samples has not been reached.

The Java Measurement reports for V5 and V6 are the same as V1.4.2. However, for V5 they are unrelated to the CPU Usage Analysis and CPU Wait Analysis reports.

Java calls that are observed with a native method at the top of the call stack are only included in the Service Time reports. This is because the J9VM does not know whether the native method is executing, waiting, or queued for execution.

Java V5 and V6 native methods are identified in the method detail pop-up window of Java Service Time reports.

To measure applications running under Java V5 or V6, you must add the -Dcom.ibm.tools.attach.enable=yes run time parameter if not already set as the system default.

When measuring applications running under Java V5 or V6, Application Performance Analyzer looks in the /tmp directory for the attach information for Java. If the default temporary directory is not /tmp, you must add the following Java run time parameter to the application being measured:
-Dcom.ibm.tools.attach.directory=/tmp/.com_ibm_tools_attach
To measure applications running under Java V5 SR10 or SR11, or Java V6 SR6 or SR7, you must run the application with UID=0. This UID=0 restriction is removed with the following Java PTFs:

When measuring applications running with -Dcom.ibm.tools.attach.enable=yes and without UID=0, J9VM may write some OPEN access violations in the system log. These can be ignored, as J9VM is attempting to open tmp directories that require UID=0 access. These directories have no significance to Application Performance Analyzer and will not affect the measurement.

If your installation does not run Application Performance Analyzer with USS superuser privileges (UID=0), then you will only be able to measure Java V5 and V6 applications that are running under the same UID as Application Performance Analyzer.

For more information about using the Java Attach API, please see the User Guide for IBM SDK for z/OS for the Java release you are running.