public static void main(String[] args) { String a = "A", b = "B", c = "C"; Collection<String> list = new ArrayList<String>(); list.add(a); list.add(b); Collection<String> list2 = new ArrayList<String>();//这句是什么意思 list2.add(b ); list2.add(c);boolean isContains = list.removeAll(list2); System.out.println(isContains); Iterator<String> it = list.iterator(); while (it.hasNext()) { String str = it.next();//这两句什么意思 System.out.println(str); }}