Java 8 default interface methods not recognized as managed bean properties in EL

Question

I am trying to setup my own JSF tag libary. So I created a composite component with an backing interfaces as a blueprint to build a backing bean for this component.

Answer 1

Working with Apache EL this works by calling the default method by its full name. Try to use it this way in your code:

#{login.getUsernameWatermark()}

Answer 2

The problem is likely caused by EL relying on reflection to find the appropriate accessor methods, but doing it in a way that fails for default methods.

Consider implementing a custom ELResolver similar to what they did here.