Non-Deterministic / Unpredictable Behavior (Again)

Hi,

Well, I've done the fine-tooth-comb routine and still have the problem
of unrepeatable results.

Here's some more information:

- I use the "immutable after initialization" (IAI) pattern extensively.

- In going over my code, I noticed many places in equals() or hashCode()
implementations that were careful not to dereference null fields. In
the light of IAI, it seems this is just a bad idea (one wants to know
if equals() or hashCode() are being called before an instance is fully
initialized), so I removed those checks. Now if equals() or hashCode()
are invoked on incompletely constituted instances, they'll throw NPEs.

- All the classes in question are descendants of one of two abstract
classes. I added implementations of equals() and hashCode() in these
abstract classes, each (pair) of which throws a "subclass
responsibility" exception when invoked.


After all this, the unrepeatability of results remains.

I am completely baffled by this.

Are there _any_ ways a properly written, single-threaded program can
yield this kind of behavior?


Randall Schulz

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