ClassCastException using ObjectInputStream in server-client application

Question

I'm trying to send an object trough sockets, but when I want to read the object in the client I got java.lang.ClassCastException.

My object is the following and I have it in both projects(Server and Client).

class Data implements Serializable{

    int height;
    int width;
    int max;
    int zoom;
    int start;
    int end;
    int xMove;
    int yMove;

    public Data(int height, int width, int max, int zoom, int start, int end, int xMove, int yMove){
        this.height = height;
        this.width = width;
        this.max = max;
        this.zoom = zoom;
        this.start = start;
        this.end = end;
        this.xMove = xMove;
        this.yMove = yMove;
    }
}

The sending part:

try{
    Data dataToSend = new Data(height, width, max, zoom, start, end, xMove, yMove);
    out.writeObject(dataToSend);
}

The receiver part:

try{
    InputStream is = socket.getInputStream();
    Data dataToRead = (Data)ois.readObject();
}

And the error message:

java.lang.ClassCastException: lab05_server.Data cannot be cast to lab05_kliens.Data

I tried everything with the same result. I can't find my mistake.

Thank you for any help.

crumbug · Accepted Answer · 2016-04-29 15:55:39Z

0

You need to have the same SerializableID added to both Data classes, take a look at :this

answered Apr 29, 2016 at 15:55

crumbug

4384 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Kiss-Budai Matyas Over a year ago

I declared this in both files: private static final long serialVersionUID = 1L; and now I got the following error: Error0 :java.io.InvalidClassException: lab05_server.Data; local class incompatible: stream classdesc serialVersionUID = 1, local class serialVersionUID = -5600343588571323555

crumbug Over a year ago

One class is correct as it is showing the ID as what you declared it : "1", the other is still picking up the default ID: "-5600343588571323555"

Kiss-Budai Matyas Over a year ago

Yepp, I found the bug, in the client in the (Datas)ois.readObject(); part the Data's constructor isn't executed(I put there a test ouptup). How can I make the casting to work? Thank you.

crumbug Over a year ago

The main take away from the link is the part that says "The two classes need to have the same package".

Kiss-Budai Matyas Over a year ago

Thank you for help, unfortunately I need the two different packages because of the server-client structure, so I will remain at passing strings. Anyhow, thank you for helping me out.

Collectives™ on Stack Overflow

ClassCastException using ObjectInputStream in server-client application

1 Answer 1

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related