Why are singleton objects more object-oriented?

Question

In Programming in Scala: A Comprehensive Step-by-Step Guide, the author said:

One way in which Scala is more object-oriented than Java is that cla

Answer 1

Singleton objects behave like classes in that they can extend/implement other types.

Can't do that in Java with just static classes -- it's pretty sugar over the Java singleton pattern with a getInstance that allows (at least) nicer namespaces/stable identifiers and hides the distinction.