archaius-core/src/main/java/com/netflix/config/DynamicProperty.java
public static DynamicProperty getInstance(String propName) {
        // This is to ensure that a configuration source is registered with
        // DynamicProperty
        if (dynamicPropertySupportImpl == null) {
            DynamicPropertyFactory.getInstance();
        }
        DynamicProperty prop = ALL_PROPS.get(propName);
        if (prop == null) {
            prop = new DynamicProperty(propName);
            DynamicProperty oldProp = ALL_PROPS.putIfAbsent(propName, prop);
            if (oldProp != null) {
                prop = oldProp;
            }
        }
        return prop;
    }
public static DynamicProperty getInstance(String propName) {
        // This is to ensure that a configuration source is registered with
        // DynamicProperty
        if (dynamicPropertySupportImpl == null) {
            DynamicPropertyFactory.getInstance();
        }
        DynamicProperty prop = ALL_PROPS.get(propName);
        if (prop == null) {
            prop = new DynamicProperty(propName);
            DynamicProperty oldProp = ALL_PROPS.putIfAbsent(propName, prop);
            if (oldProp != null) {
                prop = oldProp;
            }
        }
        return prop;
    }
Gets the DynamicProperty for a given property name.
This may be a previously constructed object,
or an object constructed on-demand to satisfy the request.

@param propName the name of the property
@return a DynamicProperty object that holds the cached value of
the configuration property named {@code propName}