On 8/16/18 4:48 PM, joe darcy wrote:
On 8/15/2018 5:10 PM, mandy chung wrote:
On 8/15/18 3:20 PM, Peter Levart wrote:
Hi Mandy,
Just a question. Why does "private Throwable exception" field in
ExceptionInInitializerError exist? Was it there before there was a
"cause" in Throwable and later still remained there because of
serialization format? Would it be possible to "simulate" its effect
for serialization using "serialPersistentFields" and
ObjectOutputStream.PutField?
Thanks for asking. I meant to mention this and it'd be nice to
follow up this in a separate issue.
The private exception field exists since 1.1 and kept there for
serialization. getException in existing releases returns the
exception field. I can't think of any way to remove the exception
field in JDK n to deserialize it with older JDK x unless JDK x was
changed to write the exception field with the cause or getException
to return cause.
Just a quick comment, it is possible, although a bit tedious, to
remove a field and retain serial compatibility if
readObject/writeObject methods are added to the new version of the
class. There are a few examples of doing this kind of conversion in
the JDK, such as for BigInteger.
Looking at the history, it turns out that these redundant fields were
removed at one point when the exception chaining support was initially
implemented but it got reverted to fix JDK-4385429. I have posted a
proposed patch to remove the private Throwable exception field and also
clean up a few other exception classes as a separate JBS issue.
http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-September/055415.html
Mandy
