Understanding Recursion in JSF: Differences Between c:forEach and ui:repeat

What are the key differences between using c:forEach and ui:repeat for recursion in JSF?

In JavaServer Faces (JSF), recursion is commonly handled using iteration controls. Two popular options for iteration are c:forEach and ui:repeat, each serving different purposes and use cases. Understanding their differences can help you choose the right one for your application.

<c:forEach items='${myList}' var='item'>
    <h:outputText value='${item}' />
</c:forEach>

<ui:repeat value='#{myBean.myList}' var='item'>
    <h:outputText value='#{item}' />
</ui:repeat>

Causes

• c:forEach is a JSTL (JavaServer Pages Standard Tag Library) tag, primarily used for non-component iteration.
• ui:repeat is a JSF UI component that allows binding to backed beans, making it more JSF-centric.

Solutions

• Use c:forEach for iterating over simple lists and arrays where JSF component features are not necessary.
• Use ui:repeat when you need to leverage JSF components or when working with JSF managed beans’ properties.

Mistake: Using c:forEach to bind JSF components results in unexpected behavior.

Solution: Always use ui:repeat for dynamic JSF component rendering.

Mistake: Not handling null lists properly, leading to NoSuchElementException.

Solution: Ensure your list is initialized and check for null values before iteration.