Question

I had a perfectly working webapp that uses Tomcat and Hibernate + c3p0.
I’m configuring hibernate programmatically, loading the model classes using getClass().getResource(/a/b/model) and adding the annotated classes.

Now, I was asked to change c3p0 and use Tomcat JDBC Connection Pool instead. I followed a couple of articles and apparently everything is setup correctly. The problem now is that I’m getting errors when trying to load the model classes and configure hibernate.

The class that is configuring hibernate (HibernateConnector.class) is located inside a jar (MyJar) in webapps\MyApp\WEB-INF\lib\MyJar.jar.

If I do getClass().getResource(“HibernateConnector.class”) I correctly obtain the path:
jar:file:/C:/apache-tomcat-7.0.29/webapps/MyApp/WEB-INF/lib/MyJar.jar!/a/b/c/HibernateConnector.class

Since I removed c3p0 and configured Tomcat Connection Pool when I ask for getClass().getResource(/a/b/model) I get file:/C:/apache-tomcat-7.0.29/work/Catalina/localhost/MyApp/loader/a/b/model

I didn’t touch any of the code regarding the loading so obviously something weird is happening with the new configuration. Does anyone have an idea on how to solve this? And why is the path changing to work/Catalina….?

Sorry for the long post and thanks in Advance!!

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Here are the changes I made to use the Tomcat Connection Pool.
In web.xml I added:

<resource-ref>
 <description>This is a MySQL database connection</description>
 <res-ref-name>jdbc/myDb</res-ref-name>
 <res-type>javax.sql.DataSource</res-type>
 <res-auth>Container</res-auth>
</resource-ref>

context.xml:

<Context antiJARLocking="true" path="MyApp">
<Resource auth="Container" driverClassName="com.mysql.jdbc.Driver" maxActive="30" maxIdle="10" maxWait="10000" name="jdbc/myDb" password="pass"
type="javax.sql.DataSource" url="jdbc:mysql://localhost/myDb" username="user"/>
</Context>

And configuring Hibernate programmatically:

props.put("hibernate.connection.datasource", "java:comp/env/jdbc/myDb");
props.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");

Answer 1

After going through a lot of resources regarding class loaders and the way tomcat loads everything, I couldn’t find anything particularly useful for my problem (although I did learn a lot on the subject).

Anyway, I started going through Tomcat’s documentation regarding the per-web-application context XML file that I listed in my question above.

I switched antiJARLocking=true to antiResourceLocking=true thinking that something was being locked and that I needed more extensive antilocking efforts. With that setting I was able to run my app. But antiResourceLocking will have a significant negative impact in the startup time, so just to try I deleted the attribute (both default to false), and that also worked!!! :-D.

My context.xml ended looking like this:

<Context path="MyApp">
   <Resource auth="Container" driverClassName="com.mysql.jdbc.Driver" maxActive="30" maxIdle="10"    maxWait="10000" name="jdbc/myDb" password="pass" type="javax.sql.DataSource" url="jdbc:mysql://localhost/myDb" username="user"/>
</Context>

Hope this helps someone in the future.