### Question:
JobUtil { public static String[] getPlaceHolders(String str) { ArrayList<String> list = new ArrayList<String>(); int[] array = null; boolean scan = true; int scanIndex = 0; while (scan) { array = getPlaceHolder(str, scanIndex); if (array != null) { String prop = str.substring(array[0] + 1, array[1]); list.add(prop); scanIndex = array[1] + 1; array = null; } else { break; } } String[] retArray = null; if (list.size() > 0) { retArray = new String[list.size()]; list.toArray(retArray); } return retArray; } private  JobUtil(); static String[] getPlaceHolders(String str); static int[] getPlaceHolder(String str, int start); static String replaceHolder(String str, String prop); static String getAndReplaceHolders(String str); static String replaceHolders(String str, String[] props); static String[] getAndReplaceHolders(String[] strArray); static boolean validateIPAddress(String address); static boolean validateFileSystemLocation(String address); static void enableProfiler(Job job, String params); static void disableProfiler(Job job); static void addClassPath(final Job job, String jars, String resources); static void addClassPath(final JobConf job, String jars,
			String resources); static void modifyOutputPath(Job job); static void modifyOutputPath(JobConf conf); static void modifyInputPath(Job job, String sampledDataPath); static void modifyInputPath(JobConf conf, String sampledDataPath);  }### Answer:
@Test public void testGetPlaceHolders() { String[] array = JobUtil.getPlaceHolders(UtilitiesConstantsTestInterface.STR); boolean check = array != null; assertTrue(check); }
@Test public void testGetPlaceHoldersNull() { String[] array = JobUtil.getPlaceHolders(UtilitiesConstantsTestInterface.STRING); boolean check = array == null; assertTrue(check); }