code: public static void setContextID(String contextID)
     {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null)
           sm.checkPermission(setPolicy);
        contextIDLocal.set(contextID);
     }
docs: <p>
  Authorization protected method used to modify the value of the policy context identifier associated with the
  thread on which this method is called.
  </p>
  
  @param contextID
  - a {@code String} that represents the value of the policy context identifier to be assigned to the
  {@code PolicyContext} for the calling thread. The value null is a legitimate value for this parameter.
  @throws SecurityException
  - if the calling {@code AccessControlContext} is not authorized by the container to call this method.