I had a problem with the tag <s:select/> that did not render correctly. It ignored the properties that I wanted to use as key and value from my beans, and instead it used the toString() method of my bean. After renaming the bean class and removing all properties, and inserting one by one, I found out that the problem was due to a property named 'parameters' in my bean.
So I guess this word is 'reserved', and there should be a warning in the tags documentation that this word cannot be used as a property in my beans, even if I don't use the property in any tag.
There is a conflict issue with this word. And I guess there might be other words that could result in the same conflict.