There&#x27;s definitely a popular DL library in Java:<p><a href="http:&#x2F;&#x2F;deeplearning4j.org&#x2F;" rel="nofollow">http:&#x2F;&#x2F;deeplearning4j.org&#x2F;</a><p>And at least one seemingly fairly current NN library:<p><a href="https:&#x2F;&#x2F;github.com&#x2F;ivan-vasilev&#x2F;neuralnetworks" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;ivan-vasilev&#x2F;neuralnetworks</a><p>An an older &quot;pre deep learning&quot; NN library called Neuroph.<p><a href="http:&#x2F;&#x2F;neuroph.sourceforge.net&#x2F;" rel="nofollow">http:&#x2F;&#x2F;neuroph.sourceforge.net&#x2F;</a><p>and another older one called JOONE:<p><a href="http:&#x2F;&#x2F;sourceforge.net&#x2F;projects&#x2F;joone&#x2F;files&#x2F;joone-engine&#x2F;" rel="nofollow">http:&#x2F;&#x2F;sourceforge.net&#x2F;projects&#x2F;joone&#x2F;files&#x2F;joone-engine&#x2F;</a><p>So in general, the answer is &quot;yes&quot; as to whether or not people are doing Neural Network &#x2F; DL  work in Java.   I can&#x27;t tell you <i>how much</i> such work is happening, or really compare Java&#x2F;Scala to Python, etc., at that level of granularity though.<p>And just for a little bit more perspective:  IBM Watson is (or was) apparently largely Java based:<p><a href="http:&#x2F;&#x2F;www.drdobbs.com&#x2F;jvm&#x2F;ibms-watson-written-mostly-in-java&#x2F;229300226" rel="nofollow">http:&#x2F;&#x2F;www.drdobbs.com&#x2F;jvm&#x2F;ibms-watson-written-mostly-in-jav...</a>