code: public class OddWord {
      interface CharHandler {
  	CharHandler handle(char c) throws Exception;
      }
      final CharHandler fwd = new CharHandler() {
  	public CharHandler handle(char c) {
  	    System.out.print(c);
  	    return (Character.isLetter(c) ? fwd : rev);
  	}
      };
      class Reverser extends Thread implements CharHandler {
  	Reverser() {
  	    setDaemon(true);
  	    start();
  	}
  	private Character ch; // For inter-thread comms
  	private char recur() throws Exception {
  	    notify();
  	    while (ch == null) wait();
  	    char c = ch, ret = c;
  	    ch = null;
  	    if (Character.isLetter(c)) {
  		ret = recur();
  		System.out.print(c);
  	    }
  	    return ret;
  	}
  	public synchronized void run() {
  	    try {
  		while (true) {
  		    System.out.print(recur());
  		    notify();
  		}
  	    } catch (Exception e) {}
  	}
  	public synchronized CharHandler handle(char c) throws Exception {
  	    while (ch != null) wait();
  	    ch = c;
  	    notify();
  	    while (ch != null) wait();
  	    return (Character.isLetter(c) ? rev : fwd);
  	}
      }
      final CharHandler rev = new Reverser();
  
      public void loop() throws Exception {
  	CharHandler handler = fwd;
  	int c;
  	while ((c = System.in.read()) >= 0) {
  	    handler = handler.handle((char) c);
  	}
      }
  
      public static void main(String[] args) throws Exception {
  	new OddWord().loop();
      }
  }
  