PHP to Java persistent process comunication

Java.java

import java.util.Scanner;

class Java {

  public static void main(String[] args) {

    Scanner s = new Scanner(System.in);

    while (s.hasNextInt()) { // <-- blocking read
      int i = s.nextInt();
      System.out.print(i + 1); // <-- send it back
      System.out.print('\n');
      System.out.flush();
    }
  }
}

PHP.php

<?php

echo 'Compiling..', PHP_EOL;
system('javac Java.java');

echo 'Starting JVM..', PHP_EOL;
$pipes = null;
$process = proc_open('java Java', [0 => ['pipe', 'r'],
                                   1 => ['pipe', 'w']], $pipes);

if (!is_resource($process)) {
  exit('ERR: Cannot create java process');
}

list($javaIn, $javaOut) = $pipes;

$i = 1;

while (true) {

  fwrite($javaIn, $i); // <-- send the number
  fwrite($javaIn, PHP_EOL);
  fflush($javaIn); 

  $reply = fgetss($javaOut); // <-- blocking read
  $i = intval($reply);

  echo $i, PHP_EOL;
  sleep(1); // <-- wait 1 second
}