Here you can find the source of copy(List
public static <T> List<T> copy(List<T> list)
//package com.java2s; import java.util.ArrayList; import java.util.List; public class Main { public static <T> List<T> copy(List<T> list) { List<T> copy = new ArrayList<T>(); for (int i = 0; i < list.size(); i++) { copy.add(list.get(i));// w ww . j av a 2s . c o m } return copy; } }