Java is an object-oriented programming language and have virtual machine platform that allows you to create compiled programs that run on nearly every platform whereas JavaScript is a scripting language that helps you create interactive web pages.
Android Apps
Enterprise Software
Scientific Computing
Big Data Analytics
General Purpose Programming of Hardware
Dynamic single page applications (SPAs)
Front-End technologies like jQuery, AngularJS, Backbone.js, Ember.js, ReactJS etc.
Mobile App Development through PhoneGap, React Native, etc.