Re: Problem : Tomcat can't compile a JSP.

[Jon Wingfield]

Ah. That rings a bell. You could be running into the problem where for 
large pages the generated java method _jspService(...) is too long 
(>32k, i think) and the compilation fails. The use of a lot of custom 
tags REALLY bumps up the size of the generated java code.

In jasper 2 (used in 4.1.x) the compilation process was completely 
rewritten and a lot of the tag boilerplate code moved out of the 
_jspService method.

So, you need to either cut down the complexity of your page (probably 
not an option), use included jsp pages (helps a lot) or migrate to the 
jasper 2 compiler.

In production we're using 4.0.6 using the jasper 2 compiler. We are 
heavily using custom tags and jasper 2 has made the jsp pages so much 
more performant :)

Steps to use jasper 2 in tomcat 4.0.x:
1) Get the latest 4.1.x release.
2) copy the files ant.jar, commons-collections.jar, jasper-compiler.jar, 
jasper-runtime.jar from the commons/lib directory of the 4.1.x distro to 
the common/lib directory of your 4.0.x installation (backup files first).
3) Remove jasper-compiler.jar, jasper-runtime.jar from the lib directory 
of your 4.0.x installation (backup files first).
4) Delete tomcat's work directory
5) Restart Tomcat

Make sure your tags are implemented as per the taglib specs otherwise 
you could see some 'issues' on migration. By default tags are pooled and 
reused so use instance variables with care ;)

Good luck,

Jon

Steven Shand wrote:

I've been having the very same problems. I narrowed it down to only 
happening on OS X and on Solaris.
It only seemed to be happening in situations where there were 'many' 
custom tags being used.

As a last resort I migrated my project to Tomcat 4.1.x and this solved 
the problem.

I guess there was something broken in the older version of Jasper that 
was fixed in the new version.

Steven Shand

On Friday, March 7, 2003, at 11:16  am, Guillaume Albini wrote:

Hi,

I use Tomcat 4.0.1 and Struts 1.0.2.

I created a JSP file using lots of Struts tags.
When Tomcat compile this JSP, i have lots of errors of type :
" Variable _jspx_th_bean_write_12 may not have been initialized.
  if (_jspx_th_bean_write_12.doEndTag() == 
javax.servlet.jsp.tagext.Tag.SKIP_PAGE)"

But when i comment one or two lines (any of them) of my JSP file, 
Tomcat compile my file without errors or warning.
Then I uncomment this lines and Tomcat can't compile my file

Then , I try to compile with javac my java file that provoke the 
errors and I don't have errors.

I dont understand this problem.

Help me please and sorry for my english !!!!

Good day

Guillaume Albini

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