code: public static void addSubjectCustomData(Subject callSubject, Hashtable<String, Object> newCred) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              Tr.entry(tc, "addSubjectCustomData", newCred);
          }
          AddPrivateCredentials action = new AddPrivateCredentials(callSubject, newCred);
          AccessController.doPrivileged(action);
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              Tr.exit(tc, "addSubjectCustomData");
          }
      }
docs: This method adds the custom Hashtable provided to the private credentials of the
  Subject passed in.
  
  @param callSubject The Subject which should have its private credentials updated with the custom Hashtable
  @param newCred The custom Hashtable with information in the format required for WebSphere
  to do a Hashtable login.