Java tutorial
//package com.java2s; //License from project: Open Source License import java.util.Collection; import java.util.List; import java.util.stream.Collectors; import java.util.stream.Stream; public class Main { /** * Joins 2 collections into one list. * * @param a Some collection * @param b Some other collection * @param <T> The type of the elements * * @return A List that contains all the elements of both collections. */ public static <T> List<T> join(Collection<? extends T> a, Collection<? extends T> b) { return Stream.concat(a.stream(), b.stream()).collect(Collectors.toList()); } }