Javascript Java Core differences between JavaScript and Java JavaScript Javascript is an interpreted language, this means it needs an interpreter ( ) to execute each line of code. The languages that belongs to this Family tend to be more flexible, smaller and platform independent (you can run it on any Operating System) that has a web browser. Object based scripting language File extension Concurrency: Doesn't support multi thread Can be run on any browser console or any text editor Integrates with HTML content and contained to the web app Dynamic Type Checking. Type checking is verified on runtime making the developer to not be obliged to declare the type of variables and making it possible to focus on productivity Prototype based. Js inheritance is prototypal (all objects can inherit directly from other objects). The hierarchy of the Objects can be achieved by assigning an Object as a prototype with a constructor function. Easier for new developers Java Java, on the other hand, is a compiled language. This Family are translated and executed directly on your System increasing speed, efficiency and control over the hardware components. Java ships with JVM (Java Virtual Machine) that makes it platform independent since it can be installed on any OS. File extension Concurrency: Support multi thread Requires JDK (Java Development Kit) Standalone language Static Type Checking. Java uses static type checking, where you have to declare the type of variable (Integer, String, Float...) and it´ll be checked on compile time. This characteristic makes Java know the type of variables used and translate into higher speed and less memory. Class Based. Java inheritance is a top to down, hierarchical and class based relationship. This comes along with the capability of abstraction since there will be a "more abstract class" that will be extended on more precise classes (example: Class animals Class mammals extends animals class canines extends animals Class dachshund extends canines) More difficult to learn for new developers Similarities between JavaScript and Java Object Oriented Programming (OOP). Both languages work in terms of objects and relationships between them. Taking this in consideration, we are able to use Inheritance, encapsulation and polymorphism on both. Front end development. Although, when you think on the web you think directly on JavaScript, Java is capable of creating Front end apps using Java Applet. Back end development. On the back end happens the opposite, you would think more of Apache, JBoss or WebSphere that are Java based but ever since Node.js came out, has become more and more used for developers to power their server side apps with JavaScript. Most common uses for Javascript and Java These programming languages are "optimized" for different purposes, this doesn't mean that you can't use Java for or javascript for other projects besides web apps. Javascript: Android apps Java: Android apps (along with Kotlin are the programming languages most used for this purpose) Large scale projects on financial environments. Scientific computing and Big Data (along with Python) Back end development Hardware and IOT (internet of things) Which one should you learn The selection between JavaScript or Java depends entirely on the project you have in mind, if you want to create a web app, then we would recommend , since it was created exactly for that and it's where it shines the most. Now, if you want to create an app that doesn't need to be run on a website, and instead, wants to make a standalone app, then Java would be the right choice. Hope you enjoy the reading and keep on the Geek Side!