發生情境：
通過sslsocket在Android API23以下正常通訊，但在Android6.0時，報錯；錯誤資訊如下：

Android端報錯：

core_booster, getBoosterConfig = false
 javax.net.ssl.SSLHandshakeException: Handshake failed
     at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:396)
     at com.android.org.conscrypt
 
.OpenSSLSocketImpl.waitForHandshake(OpenSSLSocketImpl.java:629)
     at com.android.org.conscrypt.OpenSSLSocketImpl.getOutputStream(OpenSSLSocketImpl.java:615)

 Caused by: javax.net.ssl.SSLProtocolException: SSL handshake terminated: ssl=0x7fa0a92880: Failure in SSL library, usually a protocol error
 error:100
 
c5410:SSL routines:ssl3_read_bytes:SSLV3_ALERT_HANDSHAKE_FAILURE (external/boringssl/src/ssl/s3_pkt.c:972 0x7f9e04c860:0x00000001)
 error:100c009f:SSL routines:ssl3_get_server_hello:HANDSHAKE_FAILURE_ON_CLIENT_HELLO (external/boringssl/src/ssl/s3_clnt.c:750 0x7f92721518:0x00000000)
     at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)
     at com
 
.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:324)

服務端報錯：

javax.net.ssl.SSLHandshakeException: no cipher suites in common
    at sun.security.ssl.Alerts.getSSLException(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
    at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
    at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
    at sun.security.ssl.ServerHandshaker.chooseCipherSuite(Unknown Source)
    at sun.security.ssl.ServerHandshaker.clientHello(Unknown Source)
    at sun.security.ssl.ServerHandshaker.processMessage(Unknown Source)
    at sun.security.ssl.Handshaker.processLoop(Unknown Source)
    at sun.security.ssl.Handshaker.process_record(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readDataRecord(Unknown Source)
    at sun.security.ssl.AppInputStream.read(Unknown Source)
    at sun.security.ssl.AppInputStream.read(Unknown Source)
    at java.io.DataInputStream.readLine(Unknown Source)
    at com.bbcvision.ssl.Server$ReceiveSocket.getHttpHeader(Server.java:209)
    at com.bbcvision.ssl.Server$ReceiveSocket.run(Server.java:236)

原因：
SSLSocket簽名演算法預設為DSA，Android6.0（API 23）以後KeyStore發生更改，不再支援DSA，但仍支援ECDSA。所以，檢視你的SSLSocket簽名演算法是否包含DSA，是的話就更換掉。若有其它原因，歡迎交流。

Android Keystore Changes

    With this release, the Android Keystore provider no 
longer supports DSA. ECDSA is still supported.
    Keys which do not require encryption at rest will no 
longer be deleted when secure lock screen is disabled or 
reset (for example, by the user or a Device Administrator).
 Keys which require encryption at rest will be deleted during these events.

這是官方文件裡的更改說明。