Title: Re: wrong behaviour when checking the equality of
two elem
JLS 5.1.7 Boxing Conversion:
If the value p being boxed is true, false, a byte, a char in the range \u0000 to \u007f, or an int or short number between -128 and 127, then let r1
and r2 be the results of any two boxing conversions of
p. It is always the case that r1 == r2.
in the discussion it states:
Ideally, boxing a given primitive value p, would
always yield an identical reference. In practice, this may not be
feasible using existing implementation techniques. The rules above are
a pragmatic compromise. The final clause above requires that certain
common values always be boxed into indistinguishable objects. The
implementation may cache these, lazily or eagerly.
For other values, this formulation disallows any assumptions about the
identity of the boxed values on the programmer's part. This would
allow (but not require) sharing of some or all of these
references.
This ensures that in most common cases, the behavior will be the
desired one, without imposing an undue performance penalty, especially
on small devices. Less memory-limited implementations might, for
example, cache all characters and shorts, as well as integers and
longs in the range of -32K - +32K.
--
Eduard de Jong
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