Highly *not* recommended. If you are lucky, you will lose data, meaning an entry might overwrite another entry. If you are not, internal counters will be incorrect, causing all sorts of problems.
Two points...
First, if you are using
Java 5.0, look into either the ConcurrentHashMap, or the ConcurrentLinkedQueue. Neither one is a list, but both allow parallel reads, and sometimes parallel writes, and both are
thread safe. And you might be able to use it with a small algorithm change.
And second, why?!?!? The operations are incredibly fast, mainly because they are incredibly simple. Isn't there better options to improving the speed of your code than to purposely try to live with race conditions?
Henry