Question

I am developing a JSF application with JPA(EclipseLink 2.0) and Primefaces.
I want to know is there any way to avoid null point exception when el calls a property of a null object. I have described the situation.
I have Bill class. There may be no or more BillItem objects with a Bill objects. Each BillItem object have Objects like Make, Country, Manufacturer, etc objects. I am displaying several properties of a bill within a single JSF file like this.

"#{billControlled.bill.billItem.modal.name}"

But if a bill is not selected, or when there are no bill items for a selected bill, the properties accessing in the el are null. I can avoid this by creating new objects for every bill, for example, new make for a new bill item, etc or by creating new properties in the controller itself for all the properties. But that is a very long way and feel like rudimentory.

Is there any good practice to avoid this null point exception in el in JSF?

Answer 1

I got the solution. Before every el, I can check null.

JSF: h:outputText; how to show a dash when the value is empty string?

<h:outputText value="#{userHandler.user.phoneNumber != null 
? userHandler.user.phoneNumber : '-'}" />

Or

<h:outputText rendered="#{userHandler.user.phoneNumber ne null}"  value="#{userHandler.user.phoneNumber}" />