Re: Printing only an 'A' to System.out

From:
"Karl Uppiano" <Karl_Uppiano@msn.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 23 Apr 2009 03:21:10 GMT
Message-ID:
<G8RHl.108$fy.38@nwrddc01.gnilink.net>
"Knute Johnson" <nospam@rabbitbrush.frazmtn.com> wrote in message
news:49efaf0c$0$25113$b9f67a60@news.newsdemon.com...

Stefan Ram wrote:

  I'll return to Java later, but first I will look at C:

  The following C program has a problem:

#include <stdio.h>
int main( void ){ printf( "A" ); }

  Readers might try to spot it themselves before
  continuing to read the following explanation of the problem.

  Spoiler:

  ISO/IEC 9899:1999 (E) states:

      ?A text stream is an ordered sequence of characters
      composed into lines, each line consisting of zero or more
      characters plus a terminating new-line character. Whether
      the last line requires a terminating new-line character is
      implementation-defined.?

    ISO/IEC 9899:1999 (E), 7.19.2#2

  Thus, the last line of a text stream might require a terminating
new-line character in some implementations. The above program,
  therefore, might not comply with some implementations, while
  the following will never have this problem.

#include <stdio.h>
int main( void ){ printf( "A\n" ); }

  Now, my question regarding Java: Is anything wrong with
  the following Java program?

public class Main
{ public static void main( final java.lang.String[] args )
  { java.lang.System.out.print( "A" ); }}

  The output might look ugly, because it might not be separated
  from text following it properly, but is there a wording
  similar to ISO/IEC 9899:1999 (E), 7.19.2#2 somewhere in a Java
  specification that might condemn this program in a similar
  manner to ISO/IEC 9899:1999 (E), 7.19.2#2?

  (7.19.2 is in C because the I/O facilities offered by the
  environment (operating system) might require a terminating
  linefeed. If a Java implementation is running in the same
  environment, it should inherit the same limitations from the
  same environment. So, if Java guarantees that the last line
  never requires a terminating new-line character, how does it
  do that? [One answer would be: by excluding those environments
  that require a terminating new-line character.])


I think the answer is in PrintStream.write(),

"write

public void write(int b)

    Writes the specified byte to this stream. If the byte is a newline and
automatic flushing is enabled then the flush method will be invoked.

    Note that the byte is written as given; to write a character that will
be translated according to the platform's default character encoding, use
the print(char) or println(char) methods."

So I think there is no guarantee that it will display without flushing but
I've never seen it happen in practice.


Would this be one of the places that Java simply cannot "abstract away"
platform-specific behavior?

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