// build a Map

Map<String, String> map = new HashMap<String, String>();

map.put("bye", "now");

// Convert it to a NativeObject (yes, this could have been done directly)

NativeObject nobj = new NativeObject();

for (Map.Entry<String, String> entry : map.entrySet()) {

    nobj.defineProperty(entry.getKey(), entry.getValue(), NativeObject.READONLY);

}

// Get Engine and place native object into the context

ScriptEngineManager factory = new ScriptEngineManager();

ScriptEngine engine = factory.getEngineByName("javascript");

engine.put("map", nobj);

// Standard Javascript dot notation prints 'now' (as it should!)

engine.eval("println(map.bye);");