<i>Java and Scala? Who uses that in ML? Python has long been the best language for ML</i><p>You&#x27;re kidding, right? Java has been <i>extremely</i> popular for ML for a long time.  Not to cast any shade on Python, but I&#x27;d say Java and Python are roughly equivalent in this regard.   Both have good libraries for various ML tasks and both are very popular in the domain.<p>For reference, a quick search on mloss.org finds 84 projects identified as &quot;Java&quot; and 105 identified as &quot;Python&quot;.  So while Python has a small edge in sheer numbers I think that supports my assertion that they roughly equivalent in terms of their popularity for ML.