RFR 8009581: Xpathexception does not honor initcause() (original) (raw)

David Holmes david.holmes at oracle.com
Fri May 24 04:26:10 UTC 2013

On 22/05/2013 2:51 AM, Jason Mehrens wrote:

Aleksej,

Actually, the readObject calls the super.initCause, because there is no initCause in XPathException. I would think that subclasses of XPE will see calls to this.initCause from readObject. That wouldn't have happened prior to this change.

I think this is why super.initCause() (or super.getCause()) must be called here. If you invoke this.xxx() then you may well be invoking a subclass specialization and you don't know what it will do.

About 'super.getCause() == null' check: yes it can be done in such way. In current version I caught the IllegalStateException to correctly process the situation when the cause was already initialized. I think you'll always have to catch ISE. If super.getCause is not null you know initCause will fail. I would think it would be cheaper to null check than to fillStackTrace. But, I haven't tested that.

I think readObject only needs to account for deserializing an older version of the exception which will have a non-null local cause, but Throwable.cause is null. That should be rare. The common case would be deserializing the new form, in which case initCause would fail. So I agree with Jason that checking super.getCause() is more efficient than always calling initCause.

David

Jason

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