writeObject / readObject question

[jeff willis]

Hi,

I have a client/server application that I've implemented using JAVA sockets.

I am getting a "class not found" exception from the server when it tries to readObject().

Here is my client set up:

  
public class client
{
out.writeObject(new myClass());
// some methods and other stuff
class  myClass
{
  // some methods and stuff
}
 
}

And my server set up (exception occurs at the readObject() line)

  
public class server
{
myClass msg  = (myClass)in.readObject();
// some methods and other stuff
class  myClass
{
  // some methods and stuff
}
 
}

Notice the "myClass" is the class of the object I want to send and receive.


Am I getting this exception because the two "myClass" classes are actually two different sub-classes?

To save time during implementation, I simply copied and pasted the myClass class into both the server and the client classes.

[Joe Ess]

Originally posted by jw wvu:

. . .the two "myClass" classes are actually two different sub-classes?

Nope. Your two myClass classes are different inner classes. If you look at the class files generated by the compiler, one will be named client$myClass and the other is server$myClass. They are unique classes which do not inherit any properties from their enclosing class. An inner class can only be accessed within the scope it is declared. For example, client$myClass can only be accessed within the client class.
A subclass is a relationship created with the "extends" keyword. A subclass inherits all the accessible members and methods of it's superclass. For example, java.lang.Integer is declared as:

 
public final class Integer extends Number implements Comparable 

so we say that Integer is a subclass of Number.
You should create a unique class called myClass and place it in both the client and server's classpath.

[jeff willis]

Yeah, it looks like I'm going to have to do that.

crap. I was hoping that the copy/paste of "myCLass" would save me some time but I guess not.

Thanks for your help.