ShareString

public class ShareString extends Thread {
  private static String printed = "";
  private final String letter;
  private final int sec;

  public ShareString(String letter, int sec) {
    this.letter = letter; this.sec = sec;
  }

  @Override
  public void run() {
    while (true) {
      append();
      try { sleep(sec * 1000); }
      catch (Exception e) { e.printStackTrace(); }
    }
  }

  private void append() {
    if (printed.endsWith("いう")) {
      System.out.println("え"); System.exit(0);
    }
    System.out.print(letter); printed += letter;
  }

  public static void main(String[] args) {
    ShareString s1 = new ShareString("あ", 2);
    ShareString s2 = new ShareString("い", 3);
    ShareString s3 = new ShareString("う", 4);
    s1.start(); s2.start(); s3.start();
  }
}