Path path = new Path(checkpointPath(superstepProgress));
FSDataInputStream in = this.fs.open(path);
BSPMessageBundle<M> bundle = new BSPMessageBundle<M>();
try {
for (int i = 0; i < numMessages; ++i) {
String className = in.readUTF();
@SuppressWarnings("unchecked")
M message = (M) ReflectionUtils.newInstance(
Class.forName(className), conf);
message.readFields(in);
bundle.addMessage(message);