番石榴缓存导致许多线程停放

Question

我发现很多java线程的状态是 java.lang.Thread.State：WAITING（停车）， jsatck指令是加载guava缓存。

   java.lang.Thread.State: WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for  <0x00000007c0e65bb8> (a com.google.common.util.concurrent.SettableFuture)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:445)
at com.google.common.util.concurrent.AbstractFuture$TrustedFuture.get(AbstractFuture.java:79)
at com.google.common.util.concurrent.Uninterruptibles.getUninterruptibly(Uninterruptibles.java:143)
at com.google.common.cache.LocalCache$LoadingValueReference.waitForValue(LocalCache.java:3573)
at com.google.common.cache.LocalCache$Segment.waitForLoadingValue(LocalCache.java:2306)
at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2195)
at com.google.common.cache.LocalCache.get(LocalCache.java:3953)
at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3957)
at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4875)

guava cache config

    CacheLoader<K, CacheValue<V>> loader = new CacheLoader<K, CacheValue<V>>() {
        @Override
        public CacheValue<V> load(final K key) throws Exception {
            try {
                return new CacheValue<V>(loadFromRemoting(key));

            } catch (Exception ex) {
                LogUtil.warn(LOGGER, ex)
                throw ex;
            }
        }

        @Override
        public ListenableFuture<CacheValue<V>> reload(final K key, final CacheValue<V> oldValue)
                throws Exception {
            // asynchronous refresh cache.
            ListenableFutureTask<CacheValue<V>> task = ListenableFutureTask
                    .create(new Callable<CacheValue<V>>() {
                        @Override
                        public CacheValue<V> call() {
                            try

                                return load(key);

                            } catch (Exception e) {
                                LogUtil.error(LOGGER, e)
                            }

                            return oldValue;
                        }
                    });

            refreshExecutor.submit(task);
            return task;
        }
    };


    loadingCache = CacheBuilder.newBuilder().maximumSize(20000)
            .refreshAfterWrite(getDuration(), TimeUnit.MINUTES).build(loader);

** jdk版本6

和番石榴版19.0 **

任何关于gauva缓存设计的文档或代码中的错误。