How to send child classes over Socket and recover them at the other end

Question

Suppose we have the following classes:

class Packet implements Serializable { ... };
class OpenConnectionPacket extends Packet { ... };
class DataPacket extends Packet { ... };
class CloseConnectionPacket extends Packet { ... };

Now, I want to be able to send an arbitrary packet like this:

Socket s = ...;
ObjectOutputStream toServer = new ObjectOutputStream(s.getOutputStream());

Packet p = ...;

toServer.writeObject(p);

and recieve it from the other end:

Socket s = ...;
ObjectInputStream fromClient = new ObjectInputStream(s.getInputStream());

Packet p = (Packet) fromClient.readObject();

Is this possible? How? (If it is, I guess is should override the writeObject() and readObject() methods, and maybe have something like a int type; or some enum in the parent class Packet in order to identify each child?)

score 1 · Accepted Answer · edited May 23 '17 at 12:11

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You don't need to override writeObject() and readObject().

It works by its default implementation until and unless you write your custom logic while serialization if needed.

For more info have a look at below links

edited May 23 '17 at 12:11

Community

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answered May 03 '14 at 10:16

Braj

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It will work with the default implementation even if p is not a Packet but a child class? – José D. May 03 '14 at 10:43
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yes there is no issue but opposite is not true. Try it yourself. – Braj May 03 '14 at 10:45

How to send child classes over Socket and recover them at the other end

1 Answers1