### Question:
SimpleTools { public static String join(Object[] objects, String glue) { if (objects == null) { return ""; } return SimpleTools.join(Arrays.asList(objects), glue); }  static long longHash(String s); static String createRandomString(int length); static String join(Object[] objects, String glue); static String join(Iterable<?> objects, String glue); static String repeat(String string, int count); static String repeat(Object o, int count); static byte[] toByteArray(InputStream is); static String byteToHexString(byte[] bytes); static int getSystemDefinedPort(); static final String sRandomStringCharSet; }### Answer:
@Test public void testJoin() { assertEquals("", SimpleTools.join((Object[]) null, "abc")); assertEquals("", SimpleTools.join(new Object[0], "dkefde")); assertEquals("a, b, c", SimpleTools.join(new Object[] { "a", 'b', "c" }, ", ")); assertEquals("10.20.30", SimpleTools.join(new Integer[] { 10, 20, 30 }, ".")); }