1) Enable passivation in cache configuration; 2) Enable eviction and set the maxEntries value less than the number of records that you put inside the cache (for example 200); 3) Put 400 records (it's not important the type you could use also unique strings) inside the cache; 4) Invoke clear method of the cache object: the map size value is the original map size (400) - maxEntries (200) set in the cache configuration instead of 0; So for example you notice that the value of the cache.size() will be 200 and not 0 and the next invocation of the clear method produce no result. The size will be greater than 0