Java tutorial
//package com.java2s; import java.util.ArrayList; import java.util.Collection; public class Main { public final static <T> void add(ArrayList<T> origin, ArrayList<T> list) { if (origin == null) { throw new IllegalArgumentException(""); } if (list == null || list.size() == 0) { return; } origin.addAll(list); } public final static int size(Collection c) { return c == null ? 0 : c.size(); } }