public boolean manageIdentities() {
    if (manageIdentities == null) {
      return (kerberosEnvProperties == null) ||
        !"false".equalsIgnoreCase(kerberosEnvProperties.get(KerberosHelper.MANAGE_IDENTITIES));
    } else {
      return manageIdentities;
    }
  }
KerberosDetails is a helper class to hold the details of the relevant Kerberos-specific
configurations so they may be passed around more easily.
ambari-server/src/main/java/org/apache/ambari/server/controller/KerberosDetails.java