Cache access

A JVM can access a shared class cache with either read-write or read-only access. Read-write access is the default and gives all users equal rights to update the cache. Use the -Xshareclasses:readonly option for read-only access.

Opening a cache as read-only makes it easier to administer operating system permissions. A cache created by one user cannot be opened read-write by other users, but other users can reduce startup time by opening the cache as read-only. Opening a cache as read-only also prevents corruption of the cache. This option can be useful on production systems where one instance of an application corrupting the cache might affect the performance of all other instances.

When a cache is opened read-only, class files of the application that are modified or moved cannot be updated in the cache. Sharing is disabled for the modified or moved containers for that JVM.



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