How do you pass a value into an ajax listener primefaces

Question

So I have

But I want to pass in the tabChange event AND an ex

Answer 1

You can replace argument obj with additional property in bean and set needed value to this property on ajax request:

<p:ajax event="tabChange" listener="#{refriedBean.onTabChange}">
  <f:setPropertyActionListener target="#{refriedBean.additionalProperty}" value="value_here"/>
</p:ajax>

See setPropertyActionListener