title: Spring Security - documentation for SPRING_SECURITY_LAST_EXCEPTION
body: <p>I am working on an application using Spring Security 3.1.0.  A piece of functionality that I need to modify is being driven by SPRING_SECURITY_LAST_EXCEPTION being set as an certain type of attribute.  I do not see any code from my organization that is setting an attribute by this name, so I have guessed that this is being set by Spring Security.</p>
  
  <p>My suspicion that it was not a name we made up was confirmed when I found many forum messages and 'how-to' blog posts referencing SPRING_SECURITY_LAST_EXCEPTION that don't address my actual issue.
  I still can't say what kind of attribute it is, because I have not found any documentation of how this attribute gets set and what is properties are.</p>
  
  <p>Please show me where I have failed to look in order to find the documentation explaining how this property gets set and what its attributes are.</p>