public BucketCache(Configuration conf) throws IOException { bucketCache = new HashMap<IntWritable, Bucket>(); for (String cachePath : PathUtils.getCachePaths(conf)) { String bucketCachePath = cachePath + BUCKET_CACHE_FOLDER; MapFile.Reader reader = new MapFile.Reader(new Path(bucketCachePath), conf); IntWritable key = new IntWritable(); Bucket value = new Bucket(); while (reader.next(key, value)) { bucketCache.put(new IntWritable(key.get()), new Bucket(value)); } } for (IntWritable i : bucketCache.keySet()) { System.out.println("Loaded bucket from cache:" + i.get() + ":" + bucketCache.get(i)); } }