Major Description
As listed in the JSP tag documentation, the following tag will always produce a tag error
<netui:bindingUpdateErrors expression="${actionForm.firstName}"/>
with a message of: Attribute 'expression' is required to have a value. The value "" is illegal. This is often caused by binding to an object with a null value.
If the above expression="${actionForm.firstName}" is changed to "actionForm.firstName", the expected behavior will be observed.
The netui test of coretags/binding/nullbinding is an example of this where the error is seen only because the expression="${ }".
From this index.jsp:
<li><netui:bindingUpdateErrors expression="${pageFlow.nullValue}" /> – Binding Errors</li>
Even though the value remains null, if the expression is changed to the following,
<li><netui:bindingUpdateErrors expression="pageFlow.nullValue" /> – Binding Errors</li>
the error will not occur even though the pageFlow value is still null.
There are three netui testRecorder tests that use this element and attribute combination:
coretags/binding/nullbinding - uses expression="${}"
coretags/binding/report - uses expression=""
tags/bindingUpdateErrors - uses expression=""
I am not sure if the example in the docs (http://beehive.apache.org/docs/1.0.1/netui/apidocs/taglib/beehive.apache.org/netui/tags-html-1.0/bindingUpdateErrors.html) and the nullbinding test are incorrect or if it is the other way around that the other two tests, even though currently producing expected results, are wrong.