Java Development Tools

I am trying to pass a parameter orderNumber (#{requestScope.orderNumber}). Class of the parameter is defined as 'java.math.BigDecimal'.

This is the method where I am trying to fetch the value in a variable:

public void checkFlow() {
        // Add event code here...
        BigDecimal orderNumber =
            (BigDecimal)getPageFlowScope().get("orderNumber");
        System.out.println("orderNumber: " + orderNumber);
        if (!orderNumber.equals(null)) {
            DCBindingContainer bc =
                (DCBindingContainer)BindingContext.getCurrent().getCurrentBindingsEntry();
            DCIteratorBinding iter =
                bc.findIteratorBinding("JdsuOntQeOrderSummaryVOIterator");
            ViewObject vo = iter.getViewObject();
            vo.setWhereClause("ORDER_NUMBER = " + orderNumber);
            vo.executeQuery();
        }
    }

But when I run the program, I am getting this error: "java.lang.String cannot be cast to java.math.BigDecimal". And this is due to

BigDecimal orderNumber = (BigDecimal)getPageFlowScope().get("orderNumber");

Where am I wrong? orderNumber if of type BigDecimal type only. Also I havent used type String anywhere.

JDev 11.1.1.6