Appendix - Common questions
- Last Updated: May 13, 2026
- 2 minute read
- Semaphore
- Documentation
The following are several questions that have been asked regarding Semaphore.
How do you change the JDK version for Semaphore after installation?
To change the JDK used by Semaphore after it has been installed, see the sections below.
Be careful to try to keep any path specified independent of version to limit changes that might be required whenever Java is updated. In the “/usr/lib/jvm” folder there are typically soft links that are updated on each upgrade of the JDK so using the directory soft link “/usr/lib/jvm/java-11-openjdk” in the Semaphore settings/scripts is much better than the version specific directory “/usr/lib/jvm/java-11-openjdk-11.0.14.0.9-1.el7_9.x86_64” and means that any upgrade of Java 11 OpenJDK will automatically allow Semaphore applications to pick up the new version.
For example, a “SEMAPHORE_JVM_LIB” setting of “/usr/lib/jvm/java-11-openjdk/lib/server/libjvm.so” is much more resilient to software updates than “/usr/lib/jvm/java-11-openjdk-11.0.14.0.9-1.el7_9.x86_64/lib/server/libjvm.so”.
Semaphore Classification Server
If you are using Language Packs you will need to update the SEMAPHORE_JVM_LIB environment variable used for Classification Server which should be set to the full file path for the location of “libjvm.so” on your system. This environment variable is normally set in “/etc/sysconfig/semaphore-cs”. If you update this file you will need to restart the “semaphore-cs” service for it to pick up the changes.
Semaphore Semantic Enhancement Server
Update the “JAVA_HOME” system environment variable used by SES. This is normally found in the “/etc/sysconfig/semaphore” file. After updating restart the “semaphore-ses” service.
Semaphore Studio
Update the “JAVA_HOME” system environment variable. This is normally found in the “/etc/sysconfig/semaphore” file. After updating restart the “semaphore” service (to restart Studio and all sub-components).