Java InetAddress不是线程安全的？

我们使用jdk1.8。例外情况如下：

Caused by: java.lang.NullPointerException
    at java.net.InetAddress$Cache.put(InetAddress.java:806)
    at java.net.InetAddress.cacheAddresses(InetAddress.java:885)
    at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1362)
    at java.net.InetAddress.getAllByName0(InetAddress.java:1276)
    at java.net.InetAddress.getAllByName(InetAddress.java:1192)
    at java.net.InetAddress.getAllByName(InetAddress.java:1126)
    at java.net.InetAddress.getByName(InetAddress.java:1076)
    at java.net.InetSocketAddress.<init>(InetSocketAddress.java:220)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:175)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:451)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:546)
    at sun.net.www.http.HttpClient.<init>(HttpClient.java:214)
    at sun.net.www.http.HttpClient.New(HttpClient.java:326)
    at sun.net.www.http.HttpClient.New(HttpClient.java:345)
    ...........
    ...........

缓存：

      ublic Cache put(String host, InetAddress[] addresses) {
            int policy = getPolicy();
            if (policy == InetAddressCachePolicy.NEVER) {
                return this;
            }

            // purge any expired entries

            if (policy != InetAddressCachePolicy.FOREVER) {

                // As we iterate in insertion order we can
                // terminate when a non-expired entry is found.
                LinkedList<String> expired = new LinkedList<>();
                long now = System.currentTimeMillis();
                for (String key : cache.keySet()) {
                    CacheEntry entry = cache.get(key);

806                    if (entry.expiration >= 0 && entry.expiration < now) {
807                        expired.add(key);
808                    } else {
809                        break;
                    }
                }

                for (String key : expired) {
                    cache.remove(key);
                }
            }

            // create new entry and add it to the cache
            // -- as a HashMap replaces existing entries we
            //    don't need to explicitly check if there is
            //    already an entry for this host.
            long expiration;
            if (policy == InetAddressCachePolicy.FOREVER) {
                expiration = -1;
            } else {
                expiration = System.currentTimeMillis() + (policy * 1000);
            }
828            CacheEntry entry = new CacheEntry(addresses, expiration);
829            cache.put(host, entry);
830            return this;
        }

ublic缓存put（字符串主机，InetAddress[]地址）{
int policy=getPolicy（）；
if（policy==InetAddressCachePolicy.NEVER）{
归还这个；
}
//清除所有过期的条目
if（policy！=InetAddressCachePolicy.FOREVER）{
//当我们按插入顺序迭代时，我们可以
//找到未过期的条目时终止。
LinkedList expired=新建LinkedList（）；
long now=System.currentTimeMillis（）；
for（字符串键：cache.keySet（））{
CacheEntry=cache.get（key）；
806如果（entry.expiration>=0&&entry.expiration

缓存是否有可能被系统中的其他代码损坏？您可以尝试在不同的JDK上运行代码吗？您是否能够可靠地复制它，如果是这样，它使用的是什么代码/输入？最后，如果您的帖子缺少详细信息，请不要粘贴“Stackoverflow said等”，这些不是详细信息，而是垃圾邮件。@Kayaman 1。缓存是否有可能被系统中的其他代码损坏？不，缓存由InetAddress管理，任何人都不能同时修改。2.你能试着在不同的JDK上运行代码吗？你能可靠地重现这一点吗？如果是的话，它发生在什么代码/输入上？抱歉，机器只有一个jdk版本，npe不会立即出现。我的问题是为什么这会抛出npe。缓存在InetAddress中的修改都已同步。如果您的帖子缺少详细信息，请不要粘贴“Stackoverflow said等”，对不起，为了方便起见，我复制了答案的源代码。缓存可能已损坏（例如通过反射），但可能性不大。您是否连接到许多不同的地址？这是有缺陷的行为，所以这就是这个问题的症结所在。@Kayaman是的，有几个客户。他们需要通过InetAddress获取主机的ip。确实，可能有一个线程修改缓存。但是我没有找到它。

      ublic Cache put(String host, InetAddress[] addresses) {
            int policy = getPolicy();
            if (policy == InetAddressCachePolicy.NEVER) {
                return this;
            }

            // purge any expired entries

            if (policy != InetAddressCachePolicy.FOREVER) {

                // As we iterate in insertion order we can
                // terminate when a non-expired entry is found.
                LinkedList<String> expired = new LinkedList<>();
                long now = System.currentTimeMillis();
                for (String key : cache.keySet()) {
                    CacheEntry entry = cache.get(key);

806                    if (entry.expiration >= 0 && entry.expiration < now) {
807                        expired.add(key);
808                    } else {
809                        break;
                    }
                }

                for (String key : expired) {
                    cache.remove(key);
                }
            }

            // create new entry and add it to the cache
            // -- as a HashMap replaces existing entries we
            //    don't need to explicitly check if there is
            //    already an entry for this host.
            long expiration;
            if (policy == InetAddressCachePolicy.FOREVER) {
                expiration = -1;
            } else {
                expiration = System.currentTimeMillis() + (policy * 1000);
            }
828            CacheEntry entry = new CacheEntry(addresses, expiration);
829            cache.put(host, entry);
830            return this;
        }