I don't really know Java, but .flatMap(...) seems to be equivalent to C# .SelectMany(...) which famously can be interpreted as a monadic bind operator. The C#

I don't really know Java, but .flatMap(...) seems to be equivalent to C# .SelectMany(...) which famously can be interpreted as a monadic bind operator. The C# query syntax from x in xs from y in GetYs(x) from z in GetZs(y) ... is equivalent to xs.SelectMany(x => GetYs(x).SelectMany(y => GetZs(y).SelectMany(z => ...))) which is similar to monadic do-notation in Haskell. So since there is monadic Scala code elsewhere in the project, I wonder if this is a result of someone thinking in Scala and translating it into Java in their head.