public String getSectionProperty(String sectionName, String propertyName, String defaultValue) {
        String value = getSectionProperty(sectionName, propertyName);
        return value != null ? value : defaultValue;
    }
Returns the value of the specified section property, or the {@code defaultValue} if the section or
property do not exist.

@param sectionName  the name of the section to add the name/value pair
@param propertyName the name of the property to add
@param defaultValue the default value to return if the section or property do not exist.
@return the value of the specified section property, or the {@code defaultValue} if the section or
property do not exist.
config/core/src/main/java/org/apache/shiro/config/Ini.java