question: public synchronized void release ( ) { if ( outputStreamCache != null ) outputStreamCache . invalidateAll ( ) ; if ( cacheDir . exists ( ) && cacheDir . isDirectory ( ) ) { for ( File cachedFile : cacheDir . listFiles ( ) ) { if ( ! cachedFile . delete ( ) ) { logger . warn ( "Unable to clear cached vector: " + cachedFile . getAbsolutePath ( ) ) ; } } } }
target:  Releases the cache and deletes files.