Here we took the opening and closing tags out of the included files. This does mean that the included files can no longer generate valid HTML pages on their own; they now depend on being included in something bigger. Something with <html><body> and </body></html> tags. But that’s the point—you’re designing these reusable chunks so that you can compose complete layouts from smaller pieces, without duplicating the code by hand. These reusable chunks aren’t meant to live on their own.
Note: this idea of stripping out the opening and closing tags applies to BOTH include mechanisms—<jsp:include> and the include directive.