@Before public void setUp() throws IOException { MapFileDemo.main(new String[] {MAP_URI}); Configuration conf = new Configuration(); fs = FileSystem.get(URI.create(MAP_URI), conf); reader = new MapFile.Reader(fs, MAP_URI, conf); key = (WritableComparable<?>) ReflectionUtils.newInstance(reader.getKeyClass(), conf); value = (Writable) ReflectionUtils.newInstance(reader.getValueClass(), conf); }