Here you can find the source of toUpperCase(String s)
public static String toUpperCase(String s)
//package com.java2s; /**/*from w w w . j av a 2 s .com*/ * Converts a line of text into an array of lower case words using a * BreakIterator.wordInstance(). * <p> * * This method is under the Jive Open Source Software License and was written * by Mark Imbriaco. * * @param text * a String of text to convert into an array of words * @return text broken up into an array of words. */ public class Main { public static char toUpperCase(char c) { return Character.toUpperCase(c); } public static String toUpperCase(String s) { if (s == null) return null; else { return s.toUpperCase(); /* * StringBuffer stringbuffer = new StringBuffer(); for(int i = 0; i < * s.length(); i++) stringbuffer.append(toUpperCase(s.charAt(i))); * * return stringbuffer.toString(); */ } } }