This week's book giveaway is in the Java 9 forum. We're giving away four copies of Java 9 Modularity: Patterns and Practices for Developing Maintainable Applications and have Sander Mak & Paul Bakker on-line! See this thread for details.
Page 353 of HFSCWCD states on the bottom "Type can be a class type, abstract type, or interface". on page 414 bullet point 4. it says "The type must be public, non-abstract, and have a public no-arg constructor."