What is the difference between <% … %> and

Question

I am adding some more functionality to a page that has the two tags mentioned in the title. I noticed that the variable I declare in <% ... %> cannot be used in <%! ... %> and vice versa. What is the difference between the two and how can I declare variables that could be used in the two tags

Answer 1

<% ... %> is used to embed some java code within the main service() method of the JSP. It is executed during the rendering of the page.

<%! ... %> is used to define code outside of the flow of the page, and therefore outside the main service() method. Typically, this was used to define utility methods that would be called from within a <% ... %> block.

Both approaches are now obsolete, however. JSP EL, JSTL and tag classes are the preferred way of doing the same thing.