docs: public static synchronized SimpleAuthenticator getInstance() {
          if (!sInitialized) {
              // Create an instance
              sInstance = new SimpleAuthenticator();
  
              // Try to set default (this may quietly fail...)
              Authenticator.setDefault(sInstance);
  
              // A hack to figure out if we really did set the authenticator
              PasswordAuthentication pa = Authenticator.requestPasswordAuthentication(null, FOURTYTWO, null, null, MAGIC);
  
              // If this test returns false, we didn't succeed, so we set the
              // instance back to null.
              if (pa == null || !MAGIC.equals(pa.getUserName()) || !("" + FOURTYTWO).equals(new String(pa.getPassword()))) {
                  sInstance = null;
              }
  
              // Done
              sInitialized = true;
          }
  
          return sInstance;
      }