Java's a great server side tech (Scala,JRuby,etc..). Why we need it in a browser beats me.. I don't seem to have CPython running in my Chrome, why should I have

Java's a great server side tech (Scala,JRuby,etc..). Why we need it in a browser beats me.. I don't seem to have CPython running in my Chrome, why should I have Java? Can't remember the last I visited a site who had it.