Java tutorial
//package com.java2s; /* * Copyright (c) 2014 Pacnet and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ public class Main { private static String colonize(String orig) { return orig.replaceAll("(?<=..)(..)", ":$1"); } }