code: public static void setDefaultSSLSocketFactory(SSLSocketFactory sf) {
          if (sf == null) {
              throw new IllegalArgumentException(
                  "no default SSLSocketFactory specified");
          }
  
          SecurityManager sm = System.getSecurityManager();
          if (sm != null) {
              sm.checkSetFactory();
          }
          defaultSSLSocketFactory = sf;
      }
docs: Sets the default <code>SSLSocketFactory</code> inherited by new
  instances of this class.
  <P>
  The socket factories are used when creating sockets for secure
  https URL connections.
  
  @param sf the default SSL socket factory
  @throws IllegalArgumentException if the SSLSocketFactory
  parameter is null.
  @throws SecurityException if a security manager exists and its
  <code>checkSetFactory</code> method does not allow
  a socket factory to be specified.
  @see #getDefaultSSLSocketFactory()