code: public static void setDefault(ProxySelector ps) {
          SecurityManager sm = System.getSecurityManager();
          if (sm != null) {
              // sm.checkPermission(SecurityConstants.SET_PROXYSELECTOR_PERMISSION);
          }
          theProxySelector = ps;
      }
docs: Sets (or unsets) the system-wide proxy selector.
  
  Note: non-standard protocol handlers may ignore this setting.
  
  @param ps The HTTP proxy selector, or
  <code>null</code> to unset the proxy selector.
  
  @throws  SecurityException
  If a security manager has been installed and it denies
  {@link NetPermission}<tt>("setProxySelector")</tt>
  
  @see #getDefault()
  @since 1.5