It is very important to keep up with SAP's recommendation to upgrade the JDK to the recommended release. If you ever take J2EE specific performance issues to SAP, upgrading to the latest JDK would be one of their recommendations. SAP note 709140 is the central note pointing to other SAP notes on JDK recommendations.
You must go through the note specific to the JVM you use to check for any pre-requisites.
Here are some steps that you will have to follow regardless of the JDK you use, when upgrading JDK.
1. Check SAP notes for pre-requisites to apply the latest recommended JDK and implement them.
2. Upgrade the JDK.
3. Reinstall "Unlimited Strength Jurisdiction Policy Files". You will have to implement this step even if you were using unrestricted policy files earlier as these files would be replaced by the upgrade.
4. Check the java vesion as <sid>adm to ensure that the new JDK is reflecting. If not, please ensure that the JDK was installed at the same path.
java -versionjava -fullversion5. If you are using SMD agents, recompile the AutoProbeConnector.jar file uysing the following command:
java -Dcom.wily.autoprobe.prependToJVMRuntimePath=/usr/java14_64/jre/lib/jclSC14/classes.zip -jar CreateAutoProbeConnector.jar -jvm /usr/java14_64 -output AutoProbeConnector.jarThe above command assumes that the java home is at /usr/java14_64. Adjust the command according to your java home.
6. Delete the instance.properties.vmprop file in the /usr/sap/<SID>/<instance>/j2ee/cluster directory.
7. If the java parameters are required to be changed for the new JDK, make those changes using config tool.
8. Start the applications and check the trace files to confirm that the new JDK is being used.
Be prepared to replace your JDK with SAP's JDK. 1.4.2 JDKs will be out of support soon and as a result SAP have released its own JDK to help continue usage of SAP applications that run on 1.4.2