“java.io.StreamCorruptedException: invalid type code: AC”- Error found while running the client code from the server-client java program [duplicate]

Answer 1

You are double opening an ObjectOutputStream on the same socket in the Server class which is causing special headers to be sent twice.

1: openSockets last line outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());

2: writeToSocket first line outputToClient = new ObjectOutputStream(clientSocket.getOutputStream());

Remove whichever one you want and it should work just fine.

As for the nullpointer you are now receiving I have a feeling that video is null in the client. In the code you have posted that would make sense because in the server you never create a video array and as such the client is just receiving null.

Answer 2

This error is caused by using more than one ObjectOutputStream on the same socket. Use the same ObjectOutputstream and ObjectInputStream for the life of the socket, at both ends. Same goes for most other stream and reader/writer types, except that the consequences of not doing so are usually even more mysterious.