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JavaServer Pages troubleshooting tips

Use this tips to troubleshoot problems with JavaServer Pages.


JavaServer Pages source code shown by the web server

If we share the document root of the WebSphere Application Server with the web server document root, a security exposure can result as the web server might display the JavaServer Pages (JSP) source file as plain text.

Problem

Use the WebSphere Web server plug-in set of rules to determine whether a given request will be handled by the WAS. When an incoming request fails to match those rules, the web server plug-in returns control to the web server so that the web server can fulfill the request. In this case, the unknown host header causes the web server plug-in to return control to the web server because the rules do not indicate that the WAS should handle it. Therefore, the web server looks for the request in the web server document root. Since the JSP source file is stored in the document root of the web server, the web server finds the file and displays it as plain text.

Suggested solution

Move the WAS JSP source file outside of the web server document root. Then, when this request comes in with the unknown host header, the plug-in returns control to the web server and the JSP source file is not found in the document root. Therefore, the web server returns a 404 File Not Found error rather than the JSP source file.


Problems displaying double-byte character set (DBCS) characters when using the @include directive

JavaServer Pages files that use the @include directive might experience problems when displaying double-byte character set (DBCS) characters. Some applications that are migrated to WAS v6.0 and later might need to be modified to comply with the JSP 2.0 specification as a result of backwards compatibility issues. The JSP 2.0 specification requires that each statically included resource must set a page encoding or content type because the character encoding for each file is determined separately, even if one file includes another using the include directive.


Problems using the JavaServer Pages (JSP) engine

If we are having difficulty using the JavaServer Pages (JSP) engine, try these steps:

  1. Determine whether other resources such as .html files or servlets are being requested and displayed correctly. If they are not, the problem probably lies at a deeper level, such as with the HTTP server.

  2. If other resources are being displayed correctly, determine whether the JSP processor has started normally:

    • (iSeries) Browse the JVM logs of the server hosting the JSP files we are trying to access. The following messages indicate that the JSP processor has started normally: 
      Extension Processor [class com.ibm.ws.jsp.webcontainerext.JSPExtensionProcessor] 
was initialized successfully. 
Extension Processor [class com.ibm.ws.jsp.webcontainerext.JSPExtensionProcessor] 
has been associated with patterns [*.jsp *.jspx *.jsw *.jsv ].
      If the JSP processor fails to load, we will see a message such as 
      No Extension Processor found for handling JSPs.
JSP Processor not defined. Skipping : jspfilename.
      in the root_dir/logs/server/SystemOut.log file

    • Browse the logs of the server hosting the JSP files we are trying to access. The following messages indicate that the JSP processor has started normally: 
      Extension Processor [class com.ibm.ws.jsp.webcontainerext.JSPExtensionProcessor] 
was initialized successfully. 
Extension Processor [class com.ibm.ws.jsp.webcontainerext.JSPExtensionProcessor] 
has been associated with patterns [*.jsp *.jspx *.jsw *.jsv ].
      If the JSP processor fails to load, we will see a message such as 
      No Extension Processor found for handling JSPs.
JSP Processor not defined. Skipping : jspfilename.
      in the server log files.

  3. If the JSP engine has started normally, the problem may be with the JSP file itself.

    • (iSeries) The JSP may have invalid JSP syntax and could not be processed by the JSP Processor. Examine the root_dir/logs/server/SystemOut.log file of the target application for invalid JSP directive syntax messages. Errors similar to the following in a browser indicate this kind of problem: 
      Message: /filename.jsp(2,1)JSPG0076E: Missing required attribute page for jsp 
             element jsp:include
      This example indicates that line 2, column 1 of the named JavaServer Pages file is missing a mandatory attribute for the jsp:include action. Similar messages are displayed for other syntax errors.

    • The JSP may have invalid JSP syntax and could not be processed by the JSP Processor. Examine the server log files of the target application for invalid JSP directive syntax messages. Errors similar to the following in a browser indicate this kind of problem: 
      Message: /filename.jsp(2,1)JSPG0076E: Missing required attribute page for jsp 
            element jsp:include
      This example indicates that line 2, column 1 of the named JavaServer Pages file is missing a mandatory attribute for the jsp:include action. Similar messages are displayed for other syntax errors.
    • Examine the target application server's SystemErr.log files for problems with invalid Java syntax. Errors similar to Message: Unable to compile class for JSP in a browser indicate this kind of problem.

      The error message output from the Javac compiler will be found in the SystemErr.log file. It might look like: 

      JSPG0091E: An error occurred at line: 2 in the file: /myJsp.jsp 
JSPG0093E: Generated servlet error: c:\WASROOT\temp\ ... 
test.war\_myJsp.java:16: myInt is already defined in com.ibm.ws.jsp20._myJsp 
int myInt = 122; String myString = "number is 122"; static int myStaticInt=22; 
int myInt=121;                    
         ^  1 error

      Correct the error in the JSP file and retry the file.

    • Examine the log files for the target application for problems with invalid Java syntax. Errors similar to Message: Unable to compile class for JSP in a browser indicate this kind of problem.

      The error message output from the Javac compiler will be found in the SystemErr.log. It might look like: 

      JSPG0091E: An error occurred at line: 2 in the file: /myJsp.jsp 
JSPG0093E: Generated servlet error: c:\WASROOT\temp\ ... 
test.war\_myJsp.java:16: myInt is already defined in com.ibm.ws.jsp20._myJsp 
int myInt = 122; String myString = "number is 122"; static int myStaticInt=22; 
int myInt=121;                    
         ^  1 error

      (ZOS) The error message output from the Javac compiler will be found in the server log files. It might look like: 

      JSPG0091E: An error occurred at line: 2 in the file: /myJsp.jsp 
JSPG0093E: Generated servlet error: c:\WASROOT\temp\ ... 
test.war\_myJsp.java:16: myInt is already defined in com.ibm.ws.jsp20._myJsp 
int myInt = 122; String myString = "number is 122"; static int myStaticInt=22; 
int myInt=121;                    
         ^  1 error

      Correct the error in the JSP file and retry the file.

IBM recommends using the High Performance Extensible Logging (HPEL) log and trace infrastructure . We view HPEL log and trace information using the logViewer .


JavaServer Pages fail to compile when using precompile

Symptom Problem Suggested solution
JavaServer Pages fail to compile during deployment through the administrative console when precompile is selected. 
SystemErr R com.ibm.websphere
 .management.exception
 .AdminException: 
ADMA0021E: Error in compiling jsps -
 xyz.war (rc=1)
JavaServer Pages fail to compile during deployment through the administrative console when precompile is selected when there is a dependency on another Java archive (JAR) file that is not available on any class path. You may use wsadmin scripting to precompile JSP files during enterprise application deployment. However to use the administrative console, then compile all JSP files before packaging the application.

  1. Add the dependent JAR to the deployment manager in a cell environment.

    1. Click System Administration > Deployment manager > Java and Process Management > Process Definition > Java Virtual Machine in the console navigation.

    2. Add fully qualified dependent JAR in class path field.

    3. Click OK.

    4. Restart deployment manager.


JSPG0089E: Mismatch found between page directive encoding Shift_JIS and xml prolog encoding UTF-8

Symptom Problem Suggested solution

The following error appears: 

JSP Processing Error

HTTP Error Code: 500

Error Message: /test.jsp(2,1) 
	/test.jsp(2,1) JSPG0089E: 
	Mismatch found between page 
	directive encoding Shift_JIS 
	and xml prolog encoding UTF-8
The pageEncoding attribute in the jsp:directive.page element is not UTF-8. JavaServer Pages must specify a prolog that matches the encoding specified in the page directive. For example, 
<?xml version="1.0" encoding="Shift_JIS"?>
<jsp:root xmlns:jsp="http://java.sun.com/
 JSP/Page" version="2.0">
<jsp:directive.page language="java" 
 contentType="text/html";
	charset=Shift_JIS pageEncoding=
	 "Shift_JIS"/>
<jsp:text>XXXXXjsp:text>XXXXX>
</jsp:root>

For additional information, see section JSP.4.1, Page Character Encoding, in the JavaServer Pages specification and section 4.3.3 and appendix F.1 of the Extensible Markup Language (XML) specification

Check if the problem is documented in topic, Diagnose and fix problems: Resources for learning. If we do not see a problem that resembles ours, or if the information provided does not solve our problem, contact IBM support for further assistance.

For current information available from IBM Support on known problems and their resolution, see the IBM Support page. The IBM Support page contains documents that can save you time gathering information needed to resolve this problem.


Related:

  • Web applications
  • Troubleshooting help from IBM
  • Use High Performance Extensible Logging to troubleshoot applications
  • View JVM logs
  • Diagnose and fix problems: Resources for learning
  • IBM Support page