Java SE 6 makes it simple to use JavaScript within Java code. Other scripting engines can also be associated with Java, but it is handy to have one provided out-of-the-box with Mozilla Rhino.

The JavaScript programming language, developed by Netscape, Inc., is not part of the Java platform. JavaScript, does not create applets or stand-alone applications.

To call Nashorn JavaScript from a Java 8 program, you basically need to make a new ScriptEngineManager instance and use that ScriptEngineManager to load the Nashorn script engine by name.

The javascript file contains a method addToViewer (theUrl), I need to get the variable 'url' from the servlet into this method.

It's a bit unclear what you mean when you say "what can I do". If you're referring to specific language features that are available to Java or C++ that are not available to JavaScript, it would be ...

First of all, JavaScript is not Java. It has nothing to do with Java (The language and its associated technologies from Sun Microsystems). To be honest, I'm not even sure why it's called JavaScript.

Differences Between Java and JavaScript It’s a very common perception thinking both Java and JavaScript are the same. But the truth is there is nothing common between them except their name Java.

To call Nashorn JavaScript from a Java 8 program, you basically need to make a new ScriptEngineManager instance and use that ScriptEngineManager to load the Nashorn script engine by name.