Question

Im’ trying to write a class BrokenObjectException class derivated from Exception.
But in Eclipse I get this error:

The serializable class BrokenObjectException does not declare a static final serialVersionUID field of type long

public class BrokenObjectException extends Exception
{
    BrokenObject(String message)
    {
        ;
    }
}

I have not understood why it asks me to declare a field.
Shouldn’t interface just force to declare some methods?
Anyway I want to have this class because I want to catch it n a different way from how I catch all exceptions, from I example I have a block:

try
{
    if(...)
        throw new Exception("wrong");
    if(...)
        throw new BrokenObjectException("wrong");
}
catch(BrokenObjectException e)
{
    // do something (action1)
    throw e;
}
catch(Exception e)
{
    // so something (action2)
    throw e;
}

So in the first catch block I have written “do something”.
This because depending on the type of exception thrown I want to do different actions.
So since BrokenObjectException is derivated from Exception it shall be catched two times.
But if a BrokenObjectException is thrown, I want to do action1 and action2, if just a normal Exception is thrown I want just to do action2.Is that possible?
And how to fix the error I’m getting?

Answer 1

That’s not an error but rather just a warning. Simply use the @SuppressWarnings("serial") annotation just above the class declaration:

@SuppressWarnings("serial")
public class BrokenObjectException extends Exception
{
    BrokenObject(String message)
    {
        ;
    }
}

What is happening is you are extending a class that implements the Serializable interface and so the compiler will warn you if you do not fully comply with its contract. To get around this (since I doubt that you’ll want to serialize objects of this class), simply use the annotation above.