gistfile1.java

import jdk.nashorn.api.scripting.ScriptUtils;

import javax.script.*;


public class LeakTest {
  public static void main(String[] args) {
    new LeakTest().run();
  }

  private String script1 =
          "function foo(conf) {\n" +
          "  java.lang.System.out.println('config.f is ' + conf.f);\n" +
          "  java.lang.System.out.println('in foo, conf stringified is ' + JSON.stringify(conf));\n" +
          "}\n" +
          "_javaobject.setFunction(foo);";

  private String script2 =
      "var conf = {f:'bar'};\n" +
      "java.lang.System.out.println('Before call, conf stringified is ' + JSON.stringify(conf));\n" +
      "foo(conf);";

  private void run() {
    try {
      ScriptEngineManager factory = new ScriptEngineManager();
      ScriptEngine engine = factory.getEngineByName("nashorn");

      // Run script1 in it's own scope
      ScriptContext ctx = new SimpleScriptContext();
      Bindings bindings = engine.createBindings();
      bindings.put("_javaobject", this);
      ctx.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
      engine.eval(script1, ctx);

      ctx = new SimpleScriptContext();
      bindings = engine.createBindings();
      bindings.put("foo", fun);
      ctx.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
      engine.eval(script2, ctx);

    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private Object fun;

  // This allows us to pass an JavaScript object from one scope to another
  public void setFunction(Object function) {
    fun = ScriptUtils.wrap(function);
  }



}