archaius-core/src/main/java/com/netflix/config/DynamicPropertyFactory.java
public <T> DynamicContextualProperty<T> getContextualProperty(String propName, T defaultValue) {
        return getContextualProperty(propName, defaultValue, null);
    }
public <T> DynamicContextualProperty<T> getContextualProperty(String propName, T defaultValue) {
        return getContextualProperty(propName, defaultValue, null);
    }
Create a new contextual property of type T

@param propName     property name
@param defaultValue default value if the property is not defined in underlying configuration
@param <T>          the type of the property value