Exceptional Puzzlers - Java Puzzlers: Traps, Pitfalls, and Corner Cases - page 95

When both the TRy block and the finally block complete abruptly, the reason for the abrupt
completion in the try block is discarded, and the whole TRy-finally statement completes abruptly
for the same reason as the finally block. In this program, the abrupt completion caused by the
return statement in the TRy block is discarded, and the TRy - finally statement completes abruptly
because of the return statement in the finally block. Simply put, the program tries to return
true but finally it returns false .
Discarding the reason for abrupt completion is almost never what you want, because the original
reason for abrupt completion might be important to the behavior of a program. It is especially
difficult to understand the behavior of a program that executes a break , continue , or return
statement in a TRy block only to have the statement's behavior vetoed by a finally block.
In summary, every finally block should complete normally, barring an unchecked exception.
Never exit a finally block with a return, break, continue , or tHRow , and never allow a
checked exception to propagate out of a finally block.
For language designers, finally blocks should perhaps be required to complete normally in the
absence of unchecked exceptions. Toward this end, a TRy-finally construct would require that the
finally block can complete normally [JLS 14.21]. A return , break , or continue statement that
transfers control out of a finally block would be disallowed, as would any statement that could
cause a checked exception to propagate out of the finally block.
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