serialization error

[Mike Mitchell]

Hey guys. Having a bit of trouble seeing why the following runtime exception is generated by the following code. Any ideas? thanks.

francoeur:java mike$ java Jesus
java.io.InvalidClassException: Car; local class incompatible: stream classdesc serialVersionUID = -1211912566949831027, local class serialVersionUID = 3719084103095121831
Exception in thread "main" java.lang.NullPointerException
at Jesus.main(Jesus.java:17)
 
 

francoeur:java mike$ cat SerialKiller.java Jesus.java Car.java 
import java.io.*;
 
public class SerialKiller {
Car c = new Car("Lazurus");
public static void main(String [] args) {
SerialKiller sk = new SerialKiller();
try {
FileOutputStream fos;
fos = new FileOutputStream("capncrunch.ser");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(sk.c);
} catch (FileNotFoundException fnfe) {
System.out.println(fnfe);
} catch (IOException ioe) {
System.out.println(ioe);
}
}
}
import java.io.*;
 
public class Jesus {
public static void main(String [] args) {
Car c = null;
try {
FileInputStream fir = new FileInputStream("capncrunch.ser");
ObjectInputStream ois = new ObjectInputStream(fir);
c = (Car) ois.readObject();
} catch (FileNotFoundException fnfe) {
System.out.println(fnfe);
} catch (IOException ioe) {
System.out.println(ioe);
} catch (ClassNotFoundException cnfe) {
System.out.println(cnfe);
}
System.out.println(c.getName());
}
}
import java.io.*;
 
public class Car implements Serializable {
        String name;   
                        
        public Car(String name) {
                this.name = name; 
        }       
        public String getName() {
                return name;
        }               
}       
class Wheel {}
francoeur:java mike$ 

[ July 08, 2008: Message edited by: Mike Mitchell ]

[Henry Wong]

Having a bit of trouble seeing why the following runtime exception is generated by the following code. Any ideas? thanks.

Did you make a recent change to the car class, but forgot to update the .ser file with an updated instance?

Henry

[subhasish nag]

hi,
may be this is due to you run Jesus.java before SerialKiller.java.Kindly check& reply.
subhasish

[Mike Mitchell]

Must have been as Henry suggested. I removed the three class files and recompiled. Then ran Jesus first to test Subhasish's idea (which resulted in a FileNotFoundException), then SerialKiller and Jesus again, this time with expected result.

Thanks much!