Write code to set Extension name
//package com.book2s; public class Main { public static void main(String[] argv) { String filename = "book2s.com"; String ext = "book2s.com"; System.out.println(setExtension(filename, ext)); }/*from w w w. jav a 2s. c om*/ public static String setExtension(String filename, String ext) { if (hasExtension(filename, ext)) return (filename); int index = filename.lastIndexOf("."); if (index == -1) return (filename + "." + ext); return (filename.substring(0, index + 1) + ext); } public static boolean hasExtension(String filename, String ext) { int index = filename.lastIndexOf("."); if (index == -1) return (false); return (filename.substring(index + 1).compareTo(ext) == 0); } }