Hi all, My code runs correctly when i run the clients one after another without using threads. I am getting this following error when i run my multi-threaded server. When a server accepts a client connection, ClientHandler is the thread that handles that client. Exception in thread "main" java.io.StreamCorruptedException: invalid stream header at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:737) at java.io.ObjectInputStream.(ObjectInputStream.java:253) at comm.DOMTransfer.(DOMTransfer.java:25) at ClientHandler.(ClientHandler.java:18) at ...