Question

Im trying to send multiple serializable objects of different classes through a single

ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());

But, I always get a

java.io.StreamCorruptedException: invalid type code: AC

Ive been through the forum and tried out.reset() but it doesnt seem to work.
Am I doing something wrong or missing something?

Please help

Answer 1

It is the stream that is corrupted, not the ObjectOutputStream. That is the name of a class.

This problem arises when you try to read the result of multiple ObjectOutputStreams with a single ObjectInputStream. It isn’t valid. ObjectOutputStream writes a header which starts with – guess what? 0xAC. So when you use a single ObjectInputStream to read a stream that has been created by multiple ObjectOutputStreams, it finds an unexpected 0xAC and throws that exception.

Solution: don’t do that. You can’t append multiple ObjectOutputStreams to a file, and you can’t use multiple ObjectOutputStreams over a socket unless you have extraordinary co-ordination sufficient to create a new ObjectInputStream at the precise point in the stream where the last ObjectOutputStream left off: instead, you must use the same ObjectInputStream and ObjectOutputStream for the life of the socket.