关于 HandshakeCompletedNotify-Thread 线程

最近诊断一个线程泄漏问题的时候, 发现大量的 HandshakeCompletedNotify-Thread 线程, 观察它的代码栈, 发现源自于 JDK 代码 sun.security.ssl.TransportContext.finishHandshake.

每次 SSL 连接建立都创建一个新的线程去做通知, 显然是有性能问题. 可是这个问题尚没有修复, 看上去为了兼容老的 API没人想修复: https://bugs.openjdk.java.net/browse/JDK-8246039

所以尽量连接重用, 减少性能开销.

创建线程栈:

HandshakeCompletedNotify-Thread
java.lang.Thread.start(Thread.java)
sun.security.ssl.TransportContext.finishHandshake(TransportContext.java:620)
sun.security.ssl.Finished$T12FinishedConsumer.onConsumeFinished(Finished.java:546)
sun.security.ssl.Finished$T12FinishedConsumer.consume(Finished.java:515)
sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:377)
sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:444)
sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:422)
sun.security.ssl.TransportContext.dispatch(TransportContext.java:182)
sun.security.ssl.SSLTransport.decode(SSLTransport.java:156)
sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1409)
sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1315)
sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:439)
sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:410)
sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:197)
sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1570)
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498)
sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:268)

这段代码:

    HandshakeStatus finishHandshake() {
        if (protocolVersion.useTLS13PlusSpec()) {
            outputRecord.tc = this;
            inputRecord.tc = this;
            cipherSuite = handshakeContext.negotiatedCipherSuite;
            inputRecord.readCipher.baseSecret =
                    handshakeContext.baseReadSecret;
            outputRecord.writeCipher.baseSecret =
                    handshakeContext.baseWriteSecret;
        }

        handshakeContext = null;
        outputRecord.handshakeHash.finish();
        inputRecord.finishHandshake();
        outputRecord.finishHandshake();
        isNegotiated = true;

        // Tell folk about handshake completion, but do it in a separate thread.
        if (transport instanceof SSLSocket &&
                sslConfig.handshakeListeners != null &&
                !sslConfig.handshakeListeners.isEmpty()) {
            HandshakeCompletedEvent hce =
                new HandshakeCompletedEvent((SSLSocket)transport, conSession);
            Thread thread = new Thread(
                null,
                new NotifyHandshake(sslConfig.handshakeListeners, hce),
                "HandshakeCompletedNotify-Thread",
                0,
                false);
            thread.start();
        }

        return HandshakeStatus.FINISHED;
    }