### Question:
NumberComparator implements Comparator<Object> { protected static char charAt(String s, int i) { if (i >= s.length()) { return '\000'; } return s.charAt(i); }  int compare(Object o1, Object o2);  }### Answer:
@Test public void testCharAt() { Character c = NumberComparator.charAt("Hola", 0); assertEquals("H", c.toString()); }