assertEquals("2", paramMap.get("b")[0]);

        paramMap = filter.parseQueryString("a=111&b=222&c=333", "UTF-8");
        assertEquals(3, paramMap.size());
        assertEquals("111", paramMap.get("a")[0]);
        assertEquals("222", paramMap.get("b")[0]);
        assertEquals("333", paramMap.get("c")[0]);

        paramMap = filter.parseQueryString("a=1&b=2&c=3&a=2", "UTF-8");