Here you can find the source of combine(List
public static <T> List<T> combine(List<T> a, List<T> b)
//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> combine(List<T> a, List<T> b) { List<T> list = new ArrayList<T>(); for (T t : a) list.add(t);//from w w w . j a v a 2 s.c o m for (T t : b) list.add(t); return list; } }