Java and JavaScript might seem like one was a direct descendant of the other, but in reality they are far from that. Java is an object oriented programming language that is capable of running on multiple operating systems with the use of an interpreter. It was created by Sun Microsystems with the objective of creating stand alone applications that works across platforms. JavaScript, on the other hand, was created by Netscape as a scripting language much like a client side version PHP. It cannot create stand alone applications, but instead resides on an internet browser.

Java was an excellent idea on paper. It allowed programmers to create a single program and expect it to work in the majority of operating systems available. It achieves this by not using a specific operating system’s native code. Instead, Java uses its own code then executes it on a virtual machine that interprets the Java code into its counterpart native code. As stated above, it looked great on paper, but in practice Java programs were significantly slower compared to programs coded in the native code. This was largely due to the fact each code needed to be processed twice; by the virtual machine then by the operating system.

JavaScript is a scripting language, and as such it isn’t compiled. A JavaScript enabled browser takes the script and process it, it would then execute the instructions on the script. The main use of JavaScript is to provide a level of interactivity to web pages that are not achievable with simple HTML. It can be used along with other technologies like AJAX to give an even more interactive experience. JavaScript can also interact with elements that are not from within its code which Java doesn’t do. Java applications can only be embedded into html pages and from that point on, the Java application works on its own.

Java and JavaScript are two very different languages, because of that they also have different requirements in order to function properly. Installing Java support in your browser does not mean that it would also be able to support JavaScript applications and vice versa.

Summary:

1. Java is an OOP programming language while Java Script is an OOP scripting language.
2. Java creates applications that run in a virtual machine or browser while JavaScript code is run on a browser only.
3. Java code needs to be compiled while JavaScript code are all in text.
4. They require different plug-ins.