There's a typo in the argument posted at the bottom: it's -Xshareclasses:none to disable the class cache altogether.

Thanks Michael, I had edited the typo in the Answer.

Added additional reference:
following URL has details on customizing -Xshareclasses:
https://www.ibm.com/support/knowledgecenter/en/SSYKE2_7.0.0/com.ibm.java.zos.70.doc/diag/appendixes/cmdline/Xshareclasses.html

few things to note :  
the -Xshareclasses:none argument to disable class sharing for a JVM process. Class sharing enables multiple JVM processes to share classes that were previously loaded and stored in the cache. The cache resides in shared memory and persists across JVM restarts. All WebSphere Application Server processes that run on JVMs, such as application servers, node agents, and deployment managers, can use class sharing to improve startup time and reduce memory footprint.

following suboptions with the -Xshareclasses option:
cacheDir= Sets the directory in which cache data is read and written. By default, is /tmp/javasharedresources on Linux, AIX®, z/OS®, and IBM® i. You must have sufficient permissions in . Nonpersistent caches are stored in shared memory and have control files that describe the location of the memory. Control files are stored in a javasharedresourcessubdirectory of the cacheDir specified. Do not move or delete control files in this directory. The listAllCaches utility, the destroyAll utility, and the expire suboption work only in the scope of a given cacheDir.  

Following is the link provides details on changing the Java virtual machine (JVM) configuration settings of a process for an application server, Dmgr and Node agent

https://www.ibm.com/support/knowledgecenter/en/SSAW57_8.5.5/com.ibm.websphere.nd.multiplatform.doc/ae/urun_rconfproc_jvm.html