title: Setting jdk.tls.client.protocols system property to TLSv1.2 not working in netty 4.1.48
body: <p>We are using the Redisson client, which uses netty to connect to a Redis server. With netty 4.1.42.Final, everything worked fine. But after upgrading to netty 4.1.48.Final, TLSv1 ClientHello is sent and therefore not able to connect to the server. Tried specifying TLSv1.2 by setting jdk.tls.client.protocols system property, but netty doesn't seem to be honoring it.</p>
  
  <p>With Java trace turned on, the following is seen in the trace file:</p>
  
  <p><strong>With netty 4.1.48, default protocol has TLSv1 only:</strong></p>
  
  <pre><code>jdk.tls.client.protocols is defined as TLSv1.2
  SSLv3 protocol was requested but was not enabled
  SUPPORTED: [TLSv1, TLSv1.1, TLSv1.2]
  SERVER_DEFAULT: [TLSv1, TLSv1.1, TLSv1.2]
  CLIENT_DEFAULT: [TLSv1.2]
  IBMJSSE2 will enable CBC protection
  12:00:41.624 [redisson-netty-2-9] DEBUG io.netty.handler.ssl.JdkSslContext - Default protocols (JDK): [TLSv1]
  </code></pre>
  
  <p><strong>With netty 4.1.42, default protocols included TLSv1.2:</strong></p>
  
  <pre><code>jdk.tls.client.protocols is defined as null
  SSLv3 protocol was requested but was not enabled
  SSLv3 protocol was requested but was not enabled
  SUPPORTED: [TLSv1, TLSv1.1, TLSv1.2]
  SERVER_DEFAULT: [TLSv1, TLSv1.1, TLSv1.2]
  CLIENT_DEFAULT: [TLSv1, TLSv1.1, TLSv1.2]
  10:18:00.008 [redisson-netty-2-23] DEBUG io.netty.handler.ssl.JdkSslContext - Default protocols (JDK): [TLSv1.2, TLSv1.1, TLSv1]
  </code></pre>
  
  <p><strong>netty 4.1.48 trace when jdk.tls.client.protocols system property is not set:</strong></p>
  
  <pre><code>jdk.tls.client.protocols is defined as null
  SSLv3 protocol was requested but was not enabled
  SSLv3 protocol was requested but was not enabled
  SUPPORTED: [TLSv1, TLSv1.1, TLSv1.2]
  SERVER_DEFAULT: [TLSv1, TLSv1.1, TLSv1.2]
  CLIENT_DEFAULT: [TLSv1, TLSv1.1, TLSv1.2]
  IBMJSSE2 will enable CBC protection
  09:54:19.626 [redisson-netty-2-25] DEBUG io.netty.handler.ssl.JdkSslContext - Default protocols (JDK): [TLSv1] 
  </code></pre>
  
  <p><strong>java -version output:</strong></p>
  
  <pre><code>java version "1.8.0_191"
  Java(TM) SE Runtime Environment (build 8.0.5.27 - pwa6480sr5fp27-20190104_01(SR5 FP27))
  IBM J9 VM (build 2.9, JRE 1.8.0 Windows 10 amd64-64-Bit Compressed References 20181219_405297 (JIT enabled, AOT enabled)
  OpenJ9   - 3f2d574
  OMR      - 109ba5b
  IBM      - e2996d1)
  JCL - 20190104_01 based on Oracle jdk8u191-b26
  </code></pre>
  
  <p>Anyone else running into this or know how to fix this?</p>
  
  <p>Thanks!</p>