How are environment properties accessed in Mule 4?

• A. MEL expressions p('name') to resolve dynamic values.
• B. Directly from DataWeave using variable references
• C. Using System.getProperty('name')
• D. Via a custom EnvironmentProvider API

Answer: (A)

In Mule 4, environment properties are accessed using the MEL function p('name'). The p function tells Mule to look up the property with the given key in the environment-specific property set loaded for the current deployment. This lets you externalize configuration so different environments (dev, test, prod) can supply different values without changing the flow itself.

Because of this, you can embed p('name') wherever a value is needed, and Mule will substitute the appropriate environment value at runtime. DataWeave can work with these values once retrieved, since MEL expressions with p() can be evaluated in places that expect a value.

Directly using DataWeave variable references isn’t the standard way to fetch environment properties, because environment properties come from the environment resolution mechanism, not from DataWeave variables alone. System.getProperty('name') would pull JVM system properties, which is a different mechanism from Mule’s environment properties. A custom EnvironmentProvider API isn’t required because Mule provides the built-in environment property resolution through p().