### Question:
ArrayHelper { public static String[] toStringArray(Collection coll) { return (String[]) coll.toArray( new String[coll.size()] ); }  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 testToStringArray() { assertArrayEquals( new String[]{ "1", "2" }, ArrayHelper.toStringArray( Arrays.asList( new String[]{ "1", "2" } ) ) ); }