code: public static <B extends ConnectionConfiguration.Builder<B,?>> B setTLSOnly(B builder) {
          builder.setEnabledSSLProtocols(new String[] { PROTO_TLSV1_2,  PROTO_TLSV1_1, PROTO_TLSV1 });
          return builder;
      }
docs: Enable only TLS. Connections created with the given ConnectionConfiguration will only support TLS.
  <p>
  According to the <a
  href="https://raw.githubusercontent.com/stpeter/manifesto/master/manifesto.txt">Encrypted
  XMPP Manifesto</a>, TLSv1.2 shall be deployed, providing fallback support for SSLv3 and
  TLSv1.1. This method goes one step beyond and upgrades the handshake to use TLSv1 or better.
  This method requires the underlying OS to support all of TLSv1.2 , 1.1 and 1.0.
  </p>
  
  @param builder the configuration builder to apply this setting to
  @param <B> Type of the ConnectionConfiguration builder.
  
  @return the given builder