FULL PRODUCT VERSION :
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
Here's an upstream bug report for:
- https://josm.openstreetmap.de/ticket/10423
- https://github.com/ypid/opening_hours.js/issues/52

where some javascript works fine with Java 7u67 but fails with Java 8u20 with this stracktrace:

java.lang.ClassCastException: Cannot cast jdk.nashorn.internal.scripts.JO12 to jdk.nashorn.internal.scripts.JO16
at sun.invoke.util.ValueConversions.newClassCastException(Unknown Source)
at sun.invoke.util.ValueConversions.castReference(Unknown Source)

We have isolated the problem to the handling of "name" property on objects but can't figure exactly what the problem is.

Here's attached a small program demonstrating the problem.

REGRESSION. Last worked in version 7u67

ADDITIONAL REGRESSION INFORMATION:
java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run attached program.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
"Success" is displayed on standard output.
ACTUAL -
ClassCastException

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.lang.ClassCastException: Cannot cast jdk.nashorn.internal.scripts.JO4 to jdk.nashorn.internal.scripts.JO8
at java.lang.invoke.MethodHandleImpl.newClassCastException(MethodHandleImpl.java:312)
at java.lang.invoke.MethodHandleImpl.castReference(MethodHandleImpl.java:307)
at jdk.nashorn.internal.runtime.AccessorProperty.getObjectValue(AccessorProperty.java:359)
at jdk.nashorn.internal.runtime.FindProperty.getObjectValue(FindProperty.java:162)
at jdk.nashorn.internal.runtime.ScriptObject.get(ScriptObject.java:2690)
at jdk.nashorn.internal.runtime.ScriptObject.get(ScriptObject.java:2707)
at jdk.nashorn.internal.scripts.Script$\^eval\_.opening_hours(<eval>:14)
at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:555)
at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:209)
at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:378)
at jdk.nashorn.api.scripting.ScriptObjectMirror.callMember(ScriptObjectMirror.java:185)
at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:505)
at jdk.nashorn.api.scripting.NashornScriptEngine.invokeFunction(NashornScriptEngine.java:227)
at Test.main(Test.java:35)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class Test {

    public static void main(String[] args) {
        String js = "function opening_hours() {\n"+
            "var other_object = { \n" +
            // Try to move the name member a
            " 'name': 'test name', \n"+
            " '2005': [], \n"+
            " '2007': [], \n"+
            " '2006': [], \n"+
            "}; \n"+
        
            "var object = { \n"+
            " 'name': 'hello', \n"+
            " // '2005': [], \n"+
            " // '2007': [], \n"+
            " // '2006': [], \n"+
            "}; \n"+
        
            // Comment out both -> ClassCastException disappears.
            "object['name']; \n"+
            "object.name; \n"+
        "}\n";
        
        try {
            ScriptEngine engine = new ScriptEngineManager().getEngineByName("JavaScript");
            engine.eval(js);
            ((Invocable) engine).invokeFunction("opening_hours");
            System.out.println("Success !");
        } catch (ScriptException | NoSuchMethodException e) {
            e.printStackTrace();
        }
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Switch back to Java 7.