/**
 *  The HelloWorldApp Class impliments an application that displays "Hello World!" to standard output
 */
public class HelloWorldApp
 {
    public static void main (String[] args)
    {
       // Display "Hello World!"
       System.out.println("Hello World!"); // end of line comment
       System.out.println("Hello World!"); /* end of line comment */
       System.out.println("Hello World!/*"); /* end of line comment */
/* this
is
a
multi
line
comment
*/
/* another comment */
// /* is this a valid comment
/*
//  */
       System.out.println("//Hello World!/*"); // is /* this valid
    }
 }

##</code><code>##

#!/usr/bin/perl
use strict;
my $infile = "HelloWorldApp.java";
my %linehash;
my $linecounter =0;
my $comment_started = 0;
my $multiline_comment;
open in, "$infile" or die "could not open $infile\n";
while (<in>)
{
## you may need to get creative in matching comments
## because java allows some fun combinations - see HelloWorld
##
## grab single line comments first else look for multiline
  if (/\/\/.*\n/ || /\/\*.*\*\//)
  {
     $linehash{$linecounter} = $_;
  }
  else
  {
## possible multiline comment start
    if ($comment_started)
    {
      $multiline_comment = $multiline_comment . $_;
## don't mess with $_ as later comparisons may need the newline in place
      chomp $multiline_comment;
      $multiline_comment = $multiline_comment . " ";
##  end of multiline comment
      if (/\*\//)
      {
        $linehash{$comment_started} = $multiline_comment;
        $comment_started = 0;
        $multiline_comment = "";
      }
    }
## start multiline comment
    if (/\/\*/)
    {
      $comment_started=$linecounter;
    }
  }
  $linecounter++;
}
my @keys = sort{$a <=> $b}(keys(%linehash));
for (@keys)
{
  print "key=$_   value=$linehash{$_}";
}