Java – why can’t the interface be final?

JLS 2.13. 1 interface modifier

If I can write and create static inner classes in interface I and provide implementations in them, why is there such a limitation

interface Type {

    // Normal
    class Value {
        private Value() {
        }

        public void print() {
            System.out.println("Test");
        }
    }

    public final Value value = new Value();
}

Solution

Incidentally, nested classes are not available when this restriction is first defined, so the problem may be why this restriction is not lifted

The last class cannot have any sub classes The method of using interfaces only to define subclasses is considered a best practice, so the two are contradictory

You can use interfaces for other things

>Comments > JavaDocs > constants > define nested classes only

But these are incidental purposes of the interface