RFR: 8264148: Update spec for exceptions retrofitted for exception chaining

[Stuart Marks]

On Wed, 24 Mar 2021 23:17:46 GMT, Joe Darcy <darcy at openjdk.org> wrote:

> 8264148: Update spec for exceptions retrofitted for exception chaining

The removal of the obsolescent "As of release 1.4, this exception has been retrofitted..." is good. Changing the calls from the other exception-getting methods to `getCause()` is also good. I'm less sure of the utility of deprecating these older methods. The deprecation will issue warning messages; is there any benefit to the calling code to migrating from the older methods to `getCause()`? If they're exactly equivalent, then I think the benefits are small, compared to the cost of dealing with warnings. Thus for most of these cases I think that not deprecating the older methods is reasonable, and perhaps the explanation should be converted to an `@apiNote`.

(The considerations for the JDK itself are different, though, which is why I support changing the call sites.)

One special case is the **public field** in `WriteAbortedException`. This is really bad and something ought to be done about this, including deprecation, and maybe more. This implies that the exception is mutable, right? Hrrmph. Isn't there a general rule that once the cause has been set (either via a constructor or via initCause) the exception is immutable? Maybe the field should be deprecated, and `getCause()` should return the cause from the superclass. That's a behavior change of course, and I don't know how to assess the compatibility impact. But the current situation just seems wrong.

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PR: https://git.openjdk.java.net/jdk/pull/3182