In my career spanning 15 years, the problem of Producer and Consumer is one that I have come across only a few times. In most programming cases, what we are doing is performing functions in a synchronous fashion where the JVM or the web container handles the complexities of multi-threading on its own. However, when writing certain kinds of use cases where we need this. Last week, I came acros one such use case that sent me 3 years back when I last did it. However, the way it was done last time was very different.