### Question:
CharComparator implements Comparator<Character> { private CharComparator() { } private  CharComparator(); int compare( Character char1, Character char2 ); static final CharComparator INSTANCE; }### Answer:
@Test public void testCharComparator() { CharComparator comparator = CharComparator.INSTANCE; assertEquals( 0, comparator.compare( null, null ) ); assertEquals( 0, comparator.compare( 'a', 'a' ) ); assertEquals( 0, comparator.compare( '\u00e9', '\u00e9' ) ); assertEquals( 1, comparator.compare( 'a', null ) ); assertEquals( -1, comparator.compare( 'A', 'a' ) ); assertEquals( 1, comparator.compare( 'a', 'A' ) ); assertEquals( -1, comparator.compare( null, 'a' ) ); assertEquals( -1, comparator.compare( 'a', 'b' ) ); }