title: Is there a public & concrete instance of Nashorn's ScriptObjectMirror available in Java?
body: <p>I'm basically wanting to go:</p>
  
  <pre><code>ScriptObjectMirror myObj = new ConcreteScriptObjectMirror();
  </code></pre>
  
  <p>And then invoke some JS like this, where <code>myObj</code> is the parameter:</p>
  
  <pre><code>function myJSFunc(param) { 
      with(param) { 
          return paramProperty; 
      } 
  } 
  </code></pre>
  
  <p>I'm doing that now, but Nashorn is complaining:</p>
  
  <blockquote>
    <p>TypeError: Cannot apply "with" to non script object</p>
  </blockquote>
  
  <p>So the Java object I pass in needs to be an instance of ScriptObjectMirror. </p>