FULL PRODUCT VERSION :
java version "1.7.0_05"
Java(TM) SE Runtime Environment (build 1.7.0_05-b05)
Java HotSpot(TM) Client VM (build 23.1-b03, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Please move to category 'scripting:api' !

Could not find a way to post this bug to this category.

A DESCRIPTION OF THE PROBLEM :
According to API Specification, ScriptEngine.eval() should return 'The value returned from the execution of the script. '.

This works for simple scripts like 'a+b;'.

As soon as a function call is involved, the returned value is an instance of 'sun.org.mozilla.javascript.internal.InterpretedFunction'.

Script Example:

add(a,b);
function add(a,b)
 {return a+b };

This behavior differs from Java 6, where the correct script result was returned.

REGRESSION. Last worked in version 6u31

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Execute the code below.

ACTUAL -
sun.org.mozilla.javascript.internal.InterpretedFunction@e76438

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;

public class EvalBug {

public static void main(String[] args) throws Exception {
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("JavaScript");
Bindings bindings = engine.createBindings();
bindings.put("a", 10);
bindings.put("b", 20);
String script = "add(a,b);\nfunction add(a,b) {return a+b };";
Object result = engine.eval(script, bindings);

System.out.println(result);
}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;

public class EvalBug {

public static void main(String[] args) throws Exception {
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("JavaScript");
Bindings bindings = engine.createBindings();
bindings.put("a", 10);
bindings.put("b", 20);
String script = "x=add(a,b);\nfunction add(a,b) {return a+b };";
engine.eval(script, bindings);
System.out.println(bindings.get("x"));
}
}