@@ -0,0 +1,294 @@
+package sfBugs;%0A%0Aimport edu.umd.cs.findbugs.annotations.CheckForNull;%0A%0Apublic class Bug1633245 %7B%0A    interface Foo %7B%0A        int f(@CheckForNull Object x);%0A    %7D%0A    %0A    static class FooImpl implements Foo %7B%0A        public int f(Object x) %7B%0A            return x.hashCode();%0A        %7D%0A    %7D%0A%0A%7D%0A

add sourceforge test case