Here you can find the source of toLowerCaseIgnoreNull(String tobeDone)
public static String toLowerCaseIgnoreNull(String tobeDone)
//package com.java2s; public class Main { public static String toLowerCaseIgnoreNull(String tobeDone) { if (tobeDone != null) { return tobeDone.toLowerCase(); }// ww w. ja va 2 s. c o m return null; } }