JavaServer Pages (JPSs) offer a number of ways to inject Java code into the Servlet code generated when a JSP is compiled.
Scriptlet code elements put the included Java code into the _jspService method. The included code needs to be complete java code (Remember the trailing semicolons.):
exciting HTML code
<% String important = new String("Very important programmer"); %>
more HTML code
Expressions are evaluated and placed into out.print() methods to be written to the output stream. The code included is an expression, not a complete Java statement, so leave off the trailing semicolon:
HTML tags
<%= important %>
HTML tags
<%= new java.util.Date() %>
Declaration elements insert the enclosed code into the body of the servlet code allowing the declaration of variables or methods:
HTML stuff
<%! private int counter = 0; %>
