Javadoc (b116) lacks @FunctionalInterface on Observer signature

Zhong Yu zhong.j.yu at
Fri Nov 22 10:09:46 PST 2013

The chance seems very small that one could accidentally add an
abstract method to an interface (without being hit by lots of
compilation errors else where).

On Fri, Nov 22, 2013 at 11:52 AM, Brian Goetz <brian.goetz at> wrote:
>> I still have no idea how the annotation is supposed to help us. Can
>> anyone provide a concrete use case for @FunctionalInterface?
> It captures design intent; the compiler assists you by enforcing that design
> intent (erroring if the class has more than one abstract method.)  Like the
> @Override annotation.

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