For my work, I was looking for a thread-safe equivalent of LinkedHashMap that would work well as the basis for an in-memory cache. I was hoping that such a class might be showing up in the JSR166y project, but 'twas not to be. After that, I tried googling for ConcurrentLinkedHashMap (my previous search had been for "concurrent LinkedHashMap" [minus the quotes]) and stumbled upon a small project at Google Code devoted to exactly what I was looking for: ConcurrentLinkedHashMap. I've been looking over the code. It seems pretty good and I might be helping out with it, but I'm not an expert with concurrency and the Java Memory Model to the extent really needed. I'm in touch with the main author, who seems very amenable to suggestions and corrections. We'll see how it works out.