I don't follow. It looks like ArrayList is throwing an exception on removeAll(null) -- perfectly valid, in the spec -- not throwing an exception when the collection contains null. Louis Wasserman wasserman.louis@gmail.com http://profiles.google.com/wasserman.louis On Tue, Feb 4, 2014 at 9:00 AM, Benedict Elliott Smith < belliottsmith@datastax.com> wrote:
Hi,
I notice this (or a related issue) has been mentioned before< http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-June/017663.html
on this list, but I'm not convinced the correct resolution was reached. We are seeing this problem thrown by antlr, but rather than a bug in antlr, as surmised on the previous exchange, it looks to me that ArrayList is imposing a new constraint that is neither declared by itself nor Collection, and is unnecessary. ArrayList happily supports null elements, so requiring that the provided collection has no null elements is surely a bug?
I've pasted the two declarations below for ease of reference. Neither javadocs describe the constraint that is imposed.
ArrayList: /** * Removes from this list all of its elements that are contained in the * specified collection. * * @param c collection containing elements to be removed from this list * @return {@code true} if this list changed as a result of the call * @throws ClassCastException if the class of an element of this list * is incompatible with the specified collection * (<a href="Collection.html#optional-restrictions">optional</a>) * @throws NullPointerException if this list contains a null element and the * specified collection does not permit null elements * (<a href="Collection.html#optional-restrictions">optional</a>), * or if the specified collection is null * @see Collection#contains(Object) */ public boolean removeAll(Collection<?> c) { Objects.requireNonNull(c); return batchRemove(c, false); }
Collection: /** * 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. * * @param c collection containing elements to be removed from this collection * @return <tt>true</tt> if this collection changed as a result of the * call * @throws UnsupportedOperationException if the <tt>removeAll</tt> method * is not supported by this collection * @throws ClassCastException if the types of one or more elements * in this collection are incompatible with the specified * collection * (<a href="#optional-restrictions">optional</a>) * @throws NullPointerException if this collection contains one or more * null elements and the specified collection does not support * null elements * (<a href="#optional-restrictions">optional</a>), * or if the specified collection is null * @see #remove(Object) * @see #contains(Object) */ boolean removeAll(Collection<?> c);