Introduction to Jasper 2 JSP Engine

Tomcat 8.0 uses the Jasper 2 JSP Engine to implement the JavaServer Pages 2.3 specification.

Jasper 2 has been redesigned to significantly improve performance over the original Jasper. In addition to general code improvements the following changes were made:

• JSP Custom Tag Pooling – The java objects instantiated for JSP Custom Tags can now be pooled and reused. This significantly boosts the performance of JSP pages which use custom tags.
• Background JSP compilation – If you make a change to a JSP page which had already been compiled Jasper 2 can recompile that page in the background. The previously compiled JSP page will still be available to serve requests. Once the new page has been compiled successfully it will replace the old page. This helps improve availability of your JSP pages on a production server.
• Recompile JSP when included page changes – Jasper 2 can now detect when a page included at compile time from a JSP has changed and then recompile the parent JSP.
• JDT used to compile JSP pages – The Eclipse JDT Java compiler is now used to perform JSP java source code compilation. This compiler loads source dependencies from the container classloader. Ant and javac can still be used.

Jasper is implemented using the servlet class org.apache.jasper.servlet.JspServlet.