Functional Interface definition

Maurice Naftalin maurice at
Mon Apr 1 01:37:42 PDT 2013

The first sentence of §9.8 is 

> A functional interface is an interface that has just one abstract method, and thus represents a single function contract.

This doesn't appear to be correct, given that §9.2 says that 

> If an interface has no direct superinterfaces, then the interface implicitly declares a public abstract member method ... corresponding to each public instance method ... declared in Object ...

True, the next paragraph of §9.8 says

> More precisely, for interface I, let M be the set of abstract methods that are members of I but that do not have the same signature as any public instance method of the class Object.

which sets the record straight, but not before a reader might have spent some time puzzling over the first sentence (as I did).  It would be more appropriate currently to say "More accurately..." rather than "More precisely...".


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