@Override
  public boolean testAdministratorCredentials() throws KerberosOperationException {
    if (!isOpen()) {
      throw new KerberosOperationException("This operation handler has not been opened");
    }
    // If this KerberosOperationHandler was successfully opened, successful authentication has
    // already occurred.
    return true;
  }
Removes an existing principal in a previously configured KDC
<p/>
The implementation is specific to a particular type of KDC.

@param principal a String containing the principal to remove
@param service   a boolean value indicating whether the principal is for a service or not
@return true if the principal was successfully removed; otherwise false
@throws KerberosOperationException
ambari-server/src/main/java/org/apache/ambari/server/serveraction/kerberos/ADKerberosOperationHandler.java