Object-oriented Hello World.

HelloWorld.java

import java.io.*;

public interface Printer {
    public void print(PrintStream stream);
}

public class ChainPrinter implements Printer {
    private final char _c;
    private final Printer _next;
    public ChainPrinter(char c, Printer next) {
        _c = c;
        _next = next;
    }
    public void print(PrintStream stream) {
        stream.print(_c);
        _next.print(stream);
    }
}

public class Terminator implements Printer {
    public void print(PrintStream stream) {
        stream.println();
    }
}

public class HelloWorld {
    public static void main(String[] args) {
        new ChainPrinter('H',
            new ChainPrinter('e',
                new ChainPrinter('l',
                    new ChainPrinter('l',
                        new ChainPrinter('o',
                            new ChainPrinter(',',
                                new ChainPrinter(' ',
                                    new ChainPrinter('W',
                                        new ChainPrinter('o',
                                            new ChainPrinter('r',
                                                new ChainPrinter('l',
                                                    new ChainPrinter('d', 
                                                        new Terminator()))))))))))))
        .print(System.out);
    }
}