Here you can find the source of copyOf(List
public static <T> List<T> copyOf(List<T> values)
//package com.java2s; //License from project: Open Source License import java.util.ArrayList; import java.util.List; public class Main { public static <T> List<T> copyOf(List<T> values) { return new ArrayList<T>(values); }//w ww .ja va 2 s . com }