WAS v8.5 > Reference > Administrator best practices

JSP run time compilation settings page

By default, the JSP engine translates a requested JSP file, compiles the .java file, and loads the compiled servlet into the run time environment. We can change the JSP engine default behavior by indicating that a JSP file must not be translated or compiled at run time, even when a .class file does not exist.

If run time compilation is disabled, you must precompile the JSP files, which provides the following advantages:

• Reduces compilation related disk operations.
• Minimizes disk storage requirements necessary for handling temporary .java files generated during a run time compilation.
• Allows you to not include the JSP source files in the application.
• Allows verification that a JSP file compiled successfully before deploying and installing the application in the product

We can disable run time JSP file compilation on a global or an individual web application basis:

• To disable the translation and compilation of JSP files for all Web applications, in the dmgr console, click...
  Servers > Server Types > WebSphere application servers > server_name > Container Settings > Web container settings > Web container > Custom properties

  Set disableJspRuntimeCompilation to true to disable translation and compilation of JSP files at run time for all web applications.

• To disable the translation and compilation of JSP files for a specific web application, set disableJspRuntimeCompilation to true in the JSP attribute assembly settings page when assembling application. Overrides the web container custom property setting.

• If neither the web container custom property nor the JSP parameter is set, the first request for a JSP file results in the translation and compilation of the JSP file when the .class file does not exist or is outdated. Subsequent requests for the file also result in translations and compilations, but only if the following conditions are met:
  • Translations are required because the .class file is outdated.
  • Reloading is enabled for the web module.
  • Reload interval is exceeded.

If you disable run time compilation and a request arrives for a JSP file that does not have a matching .class file, the JSP engine returns the following 404 error to the browser:

Error 404: SRVE0200E: Servlet [org.apache.jsp._jsp1]: Could not find required servlet class - _jsp1.class

In this case, an exception is written to the System Out (SYSOUT) and First Failure Data Capture (FFDC) logs. .

If a JSP file has a matching .class file but that file is out of date, the JSP engine still loads the .class file into memory.

Related concepts:

JSP

Related

Develop web applications

Reference:

Custom property settings
Web container custom properties

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