Doug Lea writes:

"It might be a nice touch to have a
validateOrder method in sorted collections. People can easily
write these themselves, but supplying standard versions might
help sensitize users to issues."

Similarly, hashmaps can be corrupted if their elements
change in any way that changes their hashCode().

It would be prohibitively expensive to perform this kind of
check on every access to the collection, but useful as a 
debugging aid and sanity check.
Posted Date : 2006-02-15 16:52:39.0

N/A

I suggest that TreeSet and HashMap could both have a method of the
same name.  Perhaps "validate" or "checkInvariants".
Improves the testability of our implementations and of client code.
Posted Date : 2006-02-15 16:55:53.0