一个非常离奇古怪的问题

[fainfy]

if (isFirstInitialization) {
                packetWriter = new PacketWriter(this);
                packetReader = new PacketReader(this);

                // If debugging is enabled, we should start the thread that will listen for
                // all packets and then log them.
                if (config.isDebuggerEnabled()) {
                    addPacketListener(debugger.getReaderListener(), null);
                    if (debugger.getWriterListener() != null) {
                        addPacketSendingListener(debugger.getWriterListener(), null);
                    }
                }
            }
            else {
                packetWriter.init();
                packetReader.init();
            }

            // Start the packet writer. This will open a XMPP stream to the server
            packetWriter.startup();
            // Start the packet reader. The startup() method will block until we
            // get an opening stream packet back from server.
            packetReader.startup();

            // Make note of the fact that we're now connected.
            connected = true;

            // Start keep alive process (after TLS was negotiated - if available)
            packetWriter.startKeepAliveProcess();

Exception in thread "Thread-33" java.lang.NullPointerException
	at org.jivesoftware.smack.XMPPConnection.initConnection(XMPPConnection.java:595)
	at org.jivesoftware.smack.XMPPConnection.connectUsingConfiguration(XMPPConnection.java:548)
	at org.jivesoftware.smack.XMPPConnection.connect(XMPPConnection.java:974)
	at net.sf.kraken.protocols.xmpp.XMPPSession$1.run(XMPPSession.java:277)
	at java.lang.Thread.run(Thread.java:619)

// Start keep alive process (after TLS was negotiated - if available)
packetWriter.startKeepAliveProcess();

在这一行中出现了空指针错误,太古怪了.在这句代码之前,还有很多使用到packetWriter的地方呢,并且该对象是在上面被创建的.
这个问题并不是必现,只是当大并发的时候会出现,不知其原因,想请高手解答.

[MiceRice]

你这个变量是局部变量还是？

有无可能在大并发情况下，被其它线程给清理了？

[fainfy]

[Quote=引用 1 楼 的回复:]

你这个变量是局部变量还是？

有无可能在大并发情况下，被其它线程给清理了？
[/Quote]
这是一个类变量.我想应该不会被其它线程给清理.
// Start keep alive process (after TLS was negotiated - if available)
packetWriter.startKeepAliveProcess();

因为每次都会到这一句才会出现null指针,而上面使用到的地方,也并没有修改packetWriter值的操作.
并且这个问题,一旦出现了之后,后面就一直会出现空指针.不会有成功的地方.