Here you can find the source of toLowerCase(List
public static List<String> toLowerCase(List<String> stringList)
//package com.java2s; //License from project: Open Source License import java.util.List; import java.util.ListIterator; public class Main { public static List<String> toLowerCase(List<String> stringList) { ListIterator<String> iterator = stringList.listIterator(); while (iterator.hasNext()) { iterator.set(iterator.next().toLowerCase()); }//from w ww . java2s . c om return stringList; } }