By looking at the source at Github, some chapters (if not all?) utilize third party tools and libraries written in Java. The community is big. For example Weka

By looking at the source at Github, some chapters (if not all?) utilize third party tools and libraries written in Java. The community is big. For example Weka is widely used for data mining (even in academia) and here it's used in the Machine Learning chapter; Drools is an excellent solution from JBoss/Red Hat used in the chapter for Expert Systems, and etc... I even see a Hadoop dependency in the code but I'm not sure (yet) in which chapter it's used. I bought the book, as a Java developer this is one of the areas I'm less experienced in, so this is a great opportunity to get up to date.