Why not multiple abstract methods in Functional Interface in Java8?

@FunctionalInterface
interface MyLambda {
    void apply1();
    int apply2(int x, int y);
}

Now using the Lambda expressions why can't Java allow below two as it clearly differentiate between the two:

MyLambda ml1 = () -> System.out.println("Hello");
MyLambda ml2 = (x, y) -> x+y;