@@ -0,0 +1,573 @@
+package sfBugs;%0A%0Aimport java.util.HashMap;%0Aimport java.util.Map;%0Aimport java.util.Set;%0A%0Apublic class Bug1830576 %7B%0A    %0A    public Set%3CString%3E keySet() %7B%0A        return null;%0A    %7D%0A%0A    public String get(String key) %7B%0A        return null;%0A    %7D%0A%0A    public static void main(String%5B%5D args) %7B%0A        Map%3CString, String%3E realMap = new HashMap%3CString, String%3E();%0A        Bug1830576 fakeMap = new Bug1830576();%0A        for (String key : fakeMap.keySet()) %7B%0A            String value = fakeMap.get(key);%0A            System.out.println(value + realMap.get(key));%0A        %7D%0A    %7D%0A%7D%0A

Test case for sourceforge bug 1830576: