getEngineByName("nashorn") returns null

Question

Cant get Nashorn engine

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
engine.eval("print('Hello World!');");

engine returns null

I am using eclipse, jdk1.8.0_11

java -version

java version "1.8.0_20-ea"

Java(TM) SE Runtime Environment (build 1.8.0_20-ea-b23)

Answer 1

Its working when I pass null param into ScriptEngineManager constructor:

ScriptEngine engine = new ScriptEngineManager(null).getEngineByName("nashorn");
engine.eval("print('Hello World!');");

from java docs

ScriptEngineManager(ClassLoader loader)

If loader is null, the script engine factories that are bundled with the platform and that are in the usual extension directories (installed extensions) are loaded.

Answer 2

Old question but in case you didn't have any joy... you might try this instead...

ScriptEngine engine = new NashornScriptEngineFactory().getScriptEngine();