Bhaskar Rao

Hi,

I haven't evaluated JAXB for performance. But one advantage I found with CASTOR was that it does not mandate the use of XSDs.

Databases can return entire ResultSets as XML which you can then transform to whatever format you want using XSLT. But again, I am not sure if the transformation itself can throw OutOfMemoryError in your case

Hi,

Have you tried using any of the memory profilers? You can run your app under a profiler which can detect memory leaks if any. Some profilers like Jprofiler (commercial) or Netbeans profiler can help you out. You can monitor heap space, GC'd objects etc.

Hi,

I dont know if its a change from Tomcat 5.0 to Tomcat 5.5. Try defining the resource name for the jdbc resource as 'jdbc/mydb' instead of 'mydb'.

I vaguely remember changing the resource name when I migrated my web app.

Hi,

Have you tried using a profiler? You can find out if there are any memory leaks in your application. I did use one such profiler to find a memory leak.

Have you checked the catalina.out for any GC logs?
I am not sure if tomcat outputs GC logs by default. if not, I think you have to change one of the the JVM args. It will then log memory used by the heap before and after each GC and the total available memory. This should at least tell you if the heap memory is used up by unused objects over time before you get the out of memory error.

Hi,

I have had this issue earlier. This is a generic error and can be thrown for various reasons. Have you tried defining the context as either 'context.xml' or yourwebappname.xml ?

have a look at the following URLTomcat config
[ December 28, 2008: Message edited by: Bhaskar Rao ]

Hi,

Tomcat does not yet provide JNDI access to external applications running outside Tomcat. The datasource created within Tomcat is available ONLY to Web Apps running inside Tomcat.

More info Tomcat Datasource

Hi,

I had faced a similar issue wherein the method DataSource.getConection() would simply hang forever without any response. My development environment had Tomcat 5.0, Connector/J 5.1.6 and MySQL 4.0.

The problem was with the MySQL connector. The Connector/J version that I used was incompatible with the version of MySQL server. I then used Connector/J 5.0.8 which resolved the problem.

which version of connector/J do you use?

You can find more info here MySQL Connector/J documentation.

Hi,

There is a way of defining global datasources. By global do you imply being accessible to all web apps? I think you can achieve it by removing the 'Path' attribute from the <context> element. The Resources thus defined should be available to all the web apps.

Hi,

This error is generated if you the container is unable to compile the requested JSP into a servlet. Have you checked your JSP for syntax errors?

Hi,

Even if you do have the MySQL driver at the web app level at WEB-INF/lib Tomcat will use the driver located at TOMCAT_HOME/common/lib. The driver located at WEB-INF/lib will not be 'visible' to Tomcat classes.

I dont see any conflict if you do have the driver at both locations, but what is the need for the driver to be available at the web app level?

Hi,

Try the latest Netbeans Milestone release. It has all the features needed to develop EJB. You can also use the GlassFish app server which is included in the release.

Are these multiple lines in a single String object? If so, use a StringTokenizer with '\n' as the delimiter to break the string into
three lines and then concatinate them together. (String s1 += strToken.nextToken())

Hi,

As far as I know, type of bean (stateless or stateful) or any other for that matter has nothing to do with JNDI. There might be some other issue.

Hi,

Q1) The replyTo queue is used to send the response after its has been processed by the MDB. Say, if some application X is waiting for the response generated by the MDB.

Q2) The Exipration value can be set using setJMSExpiration method of javax.jms .Message.

Q3) The blackout queue is usually vendor specific.

Have you added a 'reference' for the bean in the web.xml where the Servlet is defined?