I was asked a question about benign data races in Java this week, so I thought I would take the opportunity to discuss one of the (only) approved patterns for benign races. So, at the risk of encouraging bad behavior (don't use data races in your code!), I will discuss the canonical example of "benign races for performance improvement". Also, I'll put in another plug for Josh Bloch's new revision of Effective Java (lgt amazon) , which I continue to recommend. As a reminder, basically, a data race is when you have one (or more) writes, and potentially some reads; they are all to the same memory location; they can happen at the same time; and that there is nothing in the program to prevent it. This is different from a race condition , which is when you just don't know the order in which two actions are going to occur. I've put more discussion of what a data race actually is at the bottom of this post. A lot of people think that it is okay to have a data
Jeremy Manson's blog, which goes into great detail either about concurrency in Java, or anything else that the author happens to feel is interesting or relevant to the target audience.