How can I run JavaScript code at server side Java code?

Question

I want to run JavaScript code at the server side. I want to manipulate result returned by JavaScript inside my Java code. How can it be done?

Answer 1

This example should clearly state how to load, evaluate and execute a Javascript function in Java:

ScriptEngineManager factory = new ScriptEngineManager();
ScriptEngine engine = factory.getEngineByName("JavaScript");
URI source_js = JavascriptExecutor.class.getResource("/file.js").toURI();
String source_text = Files.readAllLines(Paths.get(source_js)).stream().collect(Collectors.joining("\n"));
engine.eval(source_text);
Invocable inv = (Invocable) engine;
Object returnValue = inv.invokeFunction("functionJsName", "functionJsParameter");
System.out.println(returnValue.toString());