### Question:
ShortCircuitCache implements Closeable { @Override public void close() { try { lock.lock(); if (closed) return; closed = true; LOG.info(this + ": closing"); maxNonMmappedEvictableLifespanMs = 0; maxEvictableMmapedSize = 0; IOUtils.cleanup(LOG, cacheCleaner); while (true) { Entry<Long, ShortCircuitReplica> entry = evictable.firstEntry(); if (entry == null) break; purge(entry.getValue()); } while (true) { Entry<Long, ShortCircuitReplica> entry = evictableMmapped.firstEntry(); if (entry == null) break; purge(entry.getValue()); } } finally { lock.unlock(); } IOUtils.cleanup(LOG, shmManager); } ShortCircuitCache(int maxTotalSize, long maxNonMmappedEvictableLifespanMs,
      int maxEvictableMmapedSize, long maxEvictableMmapedLifespanMs,
      long mmapRetryTimeoutMs, long staleThresholdMs, int shmInterruptCheckMs); static ShortCircuitCache fromConf(Configuration conf); long getMmapRetryTimeoutMs(); long getStaleThresholdMs(); ShortCircuitReplicaInfo fetchOrCreate(ExtendedBlockId key,
      ShortCircuitReplicaCreator creator); @Override void close(); @VisibleForTesting // ONLY for testing void accept(CacheVisitor visitor); @Override String toString(); Slot allocShmSlot(DatanodeInfo datanode,
        DomainPeer peer, MutableBoolean usedPeer,
        ExtendedBlockId blockId, String clientName); void freeSlot(Slot slot); void scheduleSlotReleaser(Slot slot); @VisibleForTesting DfsClientShmManager getDfsClientShmManager(); static final Log LOG; }### Answer:
@Test(timeout=60000) public void testCreateAndDestroy() throws Exception { ShortCircuitCache cache = new ShortCircuitCache(10, 1, 10, 1, 1, 10000, 0); cache.close(); }