Re: Is a byte data type really a 32-bit int in the JVM?

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 04 Feb 2008 09:59:22 -0500
Message-ID:
<Nv-dnVz4XOfXtTranZ2dnUVZ_jSdnZ2d@comcast.com>
Mike Schilling wrote:

Arne Vajh?Wj wrote:

Lew wrote:

Robert Dodier wrote:

Lew wrote:

Digital Puer wrote:

Is a byte data type really a 32-bit int in the JVM? More
specifically, if I have an an array of N byte types, are N
32-bit ints actually allocated underneath? I am writing
a memory-sensitive application and would appreciate
some insight.

 From our point of view as Java programmers, we don't care.

Speak for yourself. Maybe you don't care, but the OP does care,
with good reason. Your sneering tone notwithstanding, you've
completely missed the point.

Honestly, I don't know how you read "sneering" into my post. I was
speaking of the separation of concerns between Java programmers and
the low-level JVM details. In that regard, we, all of us, need not
worry about the JVM implementation as long as we are consistent
with
Java semantics.

I assure you my post was intended strictly as a technical
discussion
on the matters the OP introduced, and that there was not any
sneering
involved.

I think the keyword in the OP was "memory-sensitive". The
implementation (using 1 or 4 bytes) should not have functional
consequences, but it can have an impact on memory usage.

It is preferable if you don't need to know about the implementation
to
be sure the app will run in the available memory. But not everyone
have that luxury.


What Arne said. There's a difference between a program being correct
and running acceptably.


Well, the difference in byte storage size wouldn't make a large difference in
most cases.

The byte [] difference could be significant, but I only addressed the question
as asked by the OP:

Is a byte data type really a 32-bit int in the JVM?


To which the answer is, "No, not really, but it gets stored in a 32-bit
location."

Others addressed the other question regarding byte []. That's the power of
Useneet - we each who answer can address the part of the original post that we
feel best able to handle.

--
Lew

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