Using the "ehcache.multi.vm.config.location" property, the "java.lang.NullPointerException: Configuration Path is Null" error occured

Issue

After configuring the "ehcache.multi.vm.config.location" property in portal-ext.properties, the following errors occurred.

ERROR [SCR Component Actor][ROOT:47] bundle com.liferay.portal.cache.ehcache.impl:4.0.33 (439)[com.liferay.portal.cache.ehcache.internal.MultiVMEhcachePortalCacheManager(2201)] : The activate method has thrown an exception
java.lang.NullPointerException: Configuration path is null
at com.liferay.portal.cache.ehcache.internal.configurator.EhcachePortalCacheManagerConfigurator.getConfigurationObjectValuePair(EhcachePortalCacheManagerConfigurator.java:59) ~[?:?]

ERROR [SystemExecutorServiceUtil-5][ROOT:47] bundle com.liferay.portal.cache.ehcache.impl:4.0.33 (439)[com.liferay.portal.cache.ehcache.internal.MultiVMEhcachePortalCacheManager(2201)] : The activate method has thrown an exception
java.lang.NullPointerException: Configuration path is null

WARN [SystemExecutorServiceUtil-5][ROOT:53] bundle com.liferay.portal.cache.impl:4.0.33 (1371)[com.liferay.portal.cache.internal.MultiVMPoolImpl(6303)] : Could not get service from ref {com.liferay.portal.kernel.cache.PortalCacheManager}={component.id=2201, component.name=com.liferay.portal.cache.ehcache.internal.MultiVMEhcachePortalCacheManager, service.id=2549, portal.cache.manager.name=MULTI_VM_PORTAL_CACHE_MANAGER, service.scope=bundle, service.bundleid=439}

Environment

Quarterly Release

Resolution

Reason for an error occured:
- The issue arises due to the incorrect path "/Liferay_Home/liferay-multi-vm.xml" and the use of the same file name, "liferay-multi-vm.xml".
Reason for not using the same file name:
- By default, in Liferay's portal.properties (located within the portal-impl.jar), the following properties are configured:
```
# Set the classpath to the location of the Ehcache config file for internal
# caches. Edit the file specified in the property
# "ehcache.multi-vm.config.location" to enable clustered cache.
#
# Env: LIFERAY_EHCACHE_PERIOD_MULTI_PERIOD_VM_PERIOD_CONFIG_PERIOD_LOCATION
# Env: LIFERAY_EHCACHE_PERIOD_SINGLE_PERIOD_VM_PERIOD_CONFIG_PERIOD_LOCATION
#
ehcache.single.vm.config.location=/ehcache/liferay-single-vm.xml
ehcache.multi.vm.config.location=/ehcache/liferay-multi-vm.xml
```
- The file name liferay-multi-vm.xml is already in use and is present within the following location: osgi/portal/com.liferay.portal.cache.ehcache.impl.jar in the ehcache folder.
- This conflict causes the issue. Changing the file name ensures there is no overlap with the default configurations provided by Liferay.
- Additionally, it is a good practice to modify both the package/directory name and the file name to make it clearer and more obvious what changes were made.
To resolve the error follow the below steps:
1. 1. Create a Folder:
    - Navigate to the classes directory at the path: tomcat/webapps/ROOT/WEB-INF/classes.
    - Create a folder such as 'cache' in the "classes" folder
  2. Modify the File Name:
    - Rename the file from liferay-multi-vm.xml to a different name, such as module-multi-vm.xml and paste it into a location: tomcat/webapps/ROOT/WEB-INF/classes/cache.
  3. Add the below property with the correct location using the relative path:
    - Example: ehcache.multi.vm.config.location=cache/module-multi-vm.xml
    - Note: Use the relative path shown in the above example instead of the absolute one.
  4. Restart the server:
    1. Delete the $LIFERAY_HOME/OSGi/state folder.
    2. Delete the $LIFERAY_HOME/Work folder
    3. Delete the tomcat-version/temp folder
    4. Delete the tomcat-version/work folder
  Note:
  1) Try the above action in a lower environment first, if all works well according to you, then only move to the production environment at your discretion.
  2) Keep the backup of your existing environment before performing the above action.
  3) Perform these operations in application server downtime, because these steps require the restart of the server.

Using the "ehcache.multi.vm.config.location" property, the "java.lang.NullPointerException: Configuration Path is Null" error occured

Issue

Environment

Resolution

Additional Information