throw new Error("No field named " + fieldName + " in " + klass.getName());
throw new IllegalArgumentException ("No field named " + fieldName + " in " + klass.getName());
    public static Object getPrivateField(Class klass, Object obj,                                         String fieldName)        throws SecurityException {        try {            Field field = klass.getDeclaredField(fieldName);            field.setAccessible(true);            return field.get(obj);        } catch (NoSuchFieldException ex) {            throw new Error("No field named " + fieldName + " in " +                            klass.getName());        } catch (IllegalAccessException ex) {            throw new Error("This can't normally happen.");        }    }