You must declare the variable or method before you use it in the JSP page. The Declaration is a JSP element use to declare the variable or methods that you can use in Java code later in the JSP page.
JSP Declaration :
<%! code %> :- Code is inserted in body of servlet class, outside of service method.
Example : The declaration must be valid in the scripting language used in the JSP file.
<%! int i = 0; %>
<%! int a, b, c; %>