ObjectInputStream readObject(): ClassNotFoundException

Question

In both client and server classes, I have an exact same inner class called Data. This Data object is being sent from the server using:

ObjectOutputStream out         


        

Answer 1

What you were trying to do is something along the lines of the following:

class TCPServer {
    /* some code */

    class Data {

    }
}

class TCPClient {
    /* some code */

    class Data {

    }
}

Then you are serializing a TCPServer$Data and trying to unserialize it as a TCPClient$Data. Instead you are going to want to be doing this:

class TCPServer {
    /* some code */

}

class TCPClient {
    /* some code */

}

class Data {
    /* some code */

}

Then make sure the Data class is available to both the client and the server programs.

Answer 2

When you use some class in two different JVMs, and you are marshalling/unmarshalling the class then the class should be exported to a common library and shared between both server and client. Having different class wont work any time.

What you are trying to do is marshall TCPServer$Data and unmarshall as TCPClient$Data. That is incompatible.