On 8/16/18 4:48 PM, joe darcy wrote:
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.
Thanks Joe. In EIIE case, ideally we should remove the private
exception field and then write that to the serialize stream.
However, PutField::put requires the field to be present in
the current class; otherwise it throws IAE.
ObjectOutputStream.PutField fields = s.putFields();
fields.put("exception", getCause());
I haven't digged the history but I assume a field in BigInteger
was not renamed/removed.
Any other suggestion would be appreciated.
Mandy
