如何从另一个ArrayList中删除在一个ArrayList中找到的值？

Question

I have two ArrayLists

ArrayList<Integer> values = new ArrayList<Integer>();
values.add(9);

That's one, here's the other:

ArrayList<Integer> values2 = new ArrayList<Integer>();
for(int j = 1; j < 10; j++){
        values2.add(j);
    }

How can I compare the two and remove 9 from the second ArrayList? I tried using a foreach statement but I kept getting

Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 9, Size: 1
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)

This had been a head-peck for some hours now and I appreciate any help you can offer

Answer 1

You use

values2.removeAll(values);

From the Javadoc for the Collection interface ( http://docs.oracle.com/javase/7/docs/api/java/util/Collection.html ) -

boolean removeAll(Collection c)

Removes all of this collection's elements that are also contained in the specified collection (optional operation). After this call returns, this collection will contain no elements in common with the specified collection.