Re: Deserialization attempt freezes program execution

From:
Silvio Bierman <sbierman@jambo-software.com>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 19 Feb 2008 10:19:10 +0100
Message-ID:
<47ba9f10$0$14355$e4fe514c@news.xs4all.nl>
Qu0ll wrote:

I have now been informed that the code I posted previously is not
entirely accurate. What's actually happening is that there is an
interface MyInterface which MyClass implements. An object of type
MyClass is being serialized on one machine and transmitted to another
where MyClass is not known explicitly. The hope was that the serialized
object would contain sufficient information so that referring to the
deserialized object as a MyInterface would be sufficient to allow the
object to be deserialized on the second machine.

Is this correct? Does the MyClass need to be on the class path of the
second machine in order for an object of type MyInterface to be
deserialized there?

If so, is there a way to dynamically instantiate the class object of
MyClass on the second machine so that it could "learn" about this class?

Revised code:

ByteArrayInputStream bais = new ByteArrayInputStream(bytes, 0,
bytes.length);
MyInterface mi = null;
try {
  ObjectInputStream ois = new ObjectInputStream(bais);
  System.out.println("Reading object...");
  Object o = ois.readObject();
  System.out.println("Object read, o = " + o + ".");
  mi = (MyInterface)o;
}
catch (Exception cnfe) {
  System.out.println("Exception!");
  cnfe.printStackTrace();
}


No, this will not work. The actual class has to be known. Serialized
objects only contain their class name, not the definition. Beware of
class version issues as well.

Silvio Bierman

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