docs: public synchronized void addRoleMapping(final String roleName) {
          HashMap<String, RoleMappingImpl> newRoles = new HashMap<String, RoleMappingImpl>(roleMappings);
          if (newRoles.containsKey(roleName) == false) {
              newRoles.put(roleName, new RoleMappingImpl(roleName));
              roleMappings = Collections.unmodifiableMap(newRoles);
          }
      }