public CacheManager getCacheManager() {
        return this.cacheManager;
    }
Returns the <tt>CacheManager</tt> used for data caching to reduce EIS round trips, or <tt>null</tt> if
caching is disabled.

@return the <tt>CacheManager</tt> used for data caching to reduce EIS round trips, or <tt>null</tt> if
caching is disabled.
core/src/main/java/org/apache/shiro/realm/CachingRealm.java