RFR JDK-8209553: ExceptionInInitializerError can have a default detail message if the cause is given (original) (raw)

mandy chung mandy.chung at oracle.com
Thu Aug 16 23:54:37 UTC 2018

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

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