Here you can find the source of toUpperCase(StringBuffer buf)
public static StringBuffer toUpperCase(StringBuffer buf)
//package com.java2s; /*/*from w ww . j a va 2 s.com*/ * Copyright (C) 2003 by Trond Aasan (trond@aasan.org). * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to: * * The Free Software Foundation, Inc., * 59 Temple Place - Suite 330 * Boston, MA 02111-1307 * USA */ public class Main { public static StringBuffer toUpperCase(StringBuffer buf) { int len = buf.length(); for (int i = 0; i < len; i++) { char lc = buf.charAt(i); char uc = Character.toUpperCase(lc); if (lc != uc) { buf.setCharAt(i, uc); } } return buf; } }