### Question:
ShardUtil { public static boolean validate(String s) { if(Strings.isNullOrEmpty(s)) { return false; } int length = s.length(); for (int i = 0; i < length; i++) { char c = s.charAt(i); if (!validate(c)) { return false; } } return true; }  static String getShardName(int id); static String getShardName(String prefix, int id); static int getShardIndex(String shard); static void validateRowIdAndRecord(String rowId, Record record); static boolean validate(String s); static void validateTableName(String tableName); static void validateShardName(String shardName);  }### Answer:
@Test public void nullFamilyAndColumnNamesShouldFail() { assertFalse("Null names should fail.", ShardUtil.validate(null)); }