Doh...
The second before I clicked submit, my network at work went down, so of course... I'm retyping. So you'll only get a short version.
I'm not clear about your meaning, so I'll supply two answers:
If you want to know if there is a plugin that lets you do rich text editing for JSP's, check out
http://www.ektron.com/wysiwyg-html-editor.cfm This is a product we use here at work, it's part of a larger toolset that is
servlet based that packages this plugin as a '3rd party enhancement'
If you meant the yellow highlighting, check out style sheets.
The site you linked has defined the following style (look at the very top of the source for the page.. it's a meta link...)
That's from the style sheet, and whenever you want that background, you'd enclose your html in < PRE > tags