### Question:
ArrayHelper { public static <T> int indexOf(T[] array, T element) { for ( int i = 0; i < array.length; i++ ) { if ( array[i].equals( element ) ) { return i; } } return -1; }  static String[] toStringArray(Collection coll); static String[][] to2DStringArray(Collection coll); static String[] slice(String[] strings, int begin, int length); static int indexOf(T[] array, T element); static boolean contains(Object[] array, Object element); static T[] concat(T[] first, T... second); static T[] concat(List<T[]> arrays); static T[] concat(T firstElement, T... array); static final int[] EMPTY_INT_ARRAY; static final String[] EMPTY_STRING_ARRAY; static final Object[] EMPTY_OBJECT_ARRAY; }### Answer:
@Test public void testIndexOf() { Object[] array = new Integer[]{ 1, 2, 3 }; Object element = 3; int expResult = 2; int result = ArrayHelper.indexOf( array, element ); assertEquals( expResult, result ); }