[Java:S2039] Don't complain about private inner classes

The rule wants me to declare visibility explicitly. That’s very fine. I support that.

But in the following case it is wrong.

public class A
{
    private static class B
    {
        int i; // FP
    }
    
    private void test()
    {
        B b = new B();
        int i = b.i;
    }
}

For private inner classes (not necessarily static) the no-modifier is not only handy, but exactly correct. Private would work, but no-modifier officially allows me to access from outside the (inner) class.

Also for closures this should be ignored, even if in this case it’s better to declare private.

public Supplier< Integer > foo()
{
    return new Supplier<>()
    {
        int counter = 0; // FP
        
        @Override
        public Integer get()
        {
            return ++counter;
        }
    };
}