Object-oriented Hello World.

HelloWorld.java

import java.io.*;

public abstract class Printer {

    protected final PrintStream _stream;

    public Printer(PrintStream stream) {
        _stream = stream;
    }
    
    public abstract void print();
}

public class ChainPrinter extends Printer {

    private final char _c;
    private final Printer _next;

    public ChainPrinter(char c, PrintStream stream, Printer next) {
        super(stream);
        _c = c;
        _next = next;
    }

    public void print() {
        _stream.print(_c);
        _next.print();
    }
}

public class Terminator extends Printer {

    public Terminator(PrintStream stream) {
        super(stream);
    }

    public void print() {
        _stream.println();
    }
}

public class HelloWorld {

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