Java Enterprise Best Practices

Consider Precompilation

An alternative to deploying JSP pages directly is to precompile them into the corresponding JSP page implementation classes and deploy only the class files. The main advantage is that the container invokes the class file immediately instead of going through the JSP container and checking if the source file has changed, resulting in slightly better performance. If you deliver applications to third parties, the fact that the JSP pages cannot be modified can be an advantage, but it can also be a disadvantage because the customer might want to adjust the look and feel of the application.

The class files for the JSP pages can be packaged in a JAR file and dropped in the WEB-INF/lib directory. In addition, the web.xml file must include mappings for all JSP page URLs to the corresponding class files:

<web-app>
   . . . 
  <servlet>
    <servlet-name>mypage</servlet-name>
    <servlet-class>org.apache.jsp.mypage$jsp</servlet-class>
  </servlet>
   . . . 
  <servlet-mapping>
    <servlet-name>mypage</servlet-name>
    <url-pattern>mypage.jsp</url-pattern>
  </servlet-mapping>
   . . . 
</web-app>

Most containers include a tool for precompiling the JSP pages in a web application. Tomcat 4, for instance, comes with a command-line tool called JspC, which can be used to compile all JSP pages and generate the required web.xml declarations, like this:

[tomcat@frontier tomcat]$ cd /usr/local/jakarta-tomcat-4.0.4/bin
[tomcat@frontier bin]$ jspc -d ~/jspsrc -webinc ~/jspsrc/web.inc 
               -webapp ../webapps/ora

The command ...