public static ManagementService getExistingManagementService(Cache cache) {
    return BaseManagementService.getExistingManagementService((InternalCache) cache);
  }
Returns the existing instance of the management service for a cache.

@param cache Cache for which to get the management service.
@return The existing management service if one exists, null otherwise.
geode-core/src/main/java/org/apache/geode/management/ManagementService.java