Here you can find the source of toUpperCase(String src)
public static String toUpperCase(String src)
//package com.java2s; //License from project: Apache License public class Main { /**//from w w w.jav a 2s .co m * Safely convert the string to uppercase. * * @return upper case representation of the String; or null if * the input string is null. */ public static String toUpperCase(String src) { if (src == null) { return null; } else { return src.toUpperCase(); } } }