protected boolean isSubTypeOf(final Value value, final Value expected) {
        Type expectedType = ((BasicValue) expected).getType();
        Type type = ((BasicValue) value).getType();
        switch (expectedType.getSort()) {
            case Type.INT:
            case Type.FLOAT:
            case Type.LONG:
            case Type.DOUBLE:
                return type.equals(expectedType);
            case Type.ARRAY:
            case Type.OBJECT:
                if ("Lnull;".equals(type.getDescriptor())) {
                    return true;
                } else if (type.getSort() == Type.OBJECT
                        || type.getSort() == Type.ARRAY)
                {
                    return isAssignableFrom(expectedType, type);
                } else {
                    return false;
                }
            default:
                throw new Error("Internal error");
        }
    }