# Default value to null instead of Set<String>
	fun get_string_set(key: JavaString): HashSet[JavaString] import HashSet[JavaString],
		HashSet[JavaString].add in "Java" `{
		Set<String> def_value = new HashSet<String>();
		Set<String> java_set = self.getStringSet(key, def_value);
		nit.app.NitObject nit_hashset = new_HashSet_of_JavaString();

		for (String element: java_set)
			HashSet_of_JavaString_add(nit_hashset, element);

		return nit_hashset;
	`}