Signals that the serialization mechanism has encountered one of several possible problems with the class of an object that is being serialized or deserialized. The classname field should contain the name of the class in question, and the getMessage( ) method is overridden to return this class name with the message.

Figure 9-28. java.io.InvalidClassException

public class InvalidClassException extends ObjectStreamException {
// Public Constructors
     public InvalidClassException(String reason);  
     public InvalidClassException(String cname, String reason);  
// Public Methods Overriding Throwable
     public String getMessage( );  
// Public Instance Fields
     public String classname;  
}