protected static Boolean getBooleanValue(Map<?, ?> map, String key, Boolean defaultValue) {
    String value = getStringValue(map, key);
    return (StringUtils.isEmpty(value)) ? defaultValue : Boolean.valueOf(value);
  }
Safely retrieves the requested value (converted to a Boolean) from the supplied Map
<p/>
The found value will be converted to a Boolean using {@link Boolean#valueOf(String)}.

@param map          a Map containing the relevant data
@param key          a String declaring the item to retrieve
@param defaultValue a Boolean value to return if the data is not found
@return a Boolean representing the requested data; or the specified default value if not found
@see Boolean#valueOf(String)
ambari-server/src/main/java/org/apache/ambari/server/state/kerberos/AbstractKerberosDescriptor.java