Re: Read a single byte from stdin

From:

Joshua Cranmer <Pidgeot18@verizon.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Mon, 13 Jul 2009 20:43:07 -0400

Message-ID:

<h3gkav$psq$1@news-int2.gatech.edu>

Martin Gregorie wrote:

Sure, but it still pays for the major JVM suppliers to keep as much code
as possible platform independent. If they restrict themselves as far as
possible to portable functions and constructs they can minimize the size
of the #ifdef forest and/or the set of platform-specific source modules.

There are problems with some areas of platform-independence. Any JVM
likely to be used in realistic conditions would have some form of JIT,
which is obviously rather processor-dependent. Also, many
high-performance JVMs will be in the stage of ?ber-optimization--there's
some code for swapping bytes in assembly in Sun's JDK.

Finally, any native code calling will have to have some form reflective
access, so one has to differentiate different function call schemes on
various processors.

Now, granted, a good JVM would isolate all of the processor or
platform-dependent code into a few classes or modules (depending on C++
or C implementation). But there is still a large remnant of dependence;
in some cases, JVMs might eschew portability in favor of speed.

--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth