Here you can find the source of charToLowerCase(char c)
public static char charToLowerCase(char c)
//package com.java2s; //License from project: Open Source License public class Main { public static char charToLowerCase(char c) { if (c >= 'A' && c <= 'Z') return (char) (c - ('A' - 'a')); return c; }/*from w w w. j av a 2s.c om*/ }