@Override
  public void init(FilterConfig filterConfig) throws ServletException {
    LOG.debug("Initializing {}", this.getClass().getName());

    if (configuration == null) {
      LOG.warn("The Ambari configuration object is not available, all default options will be assumed.");
    } else {
      processConfig(configuration);
    }
  }
The value for the Charset HTTP response header.
ambari-server/src/main/java/org/apache/ambari/server/security/AbstractSecurityHeaderFilter.java