Java tutorial
public class Main { public static void main(String[] args) { String input = "ThisIsATest"; // split into words String[] words = input.split("(?=[A-Z])"); words[0] = capitalizeFirstLetter(words[0]); // join StringBuilder builder = new StringBuilder(); for (String s : words) { builder.append(s).append(" "); } System.out.println(builder.toString()); } private static String capitalizeFirstLetter(String in) { return in.substring(0, 1).toUpperCase() + in.substring(1); } }