Major Differences Between Tomcat 5.0 and Tomcat 5.5

By Alex Carter on October 8, 2024

Apache Tomcat 5.0 and 5.5 are older versions that support Java web applications using Servlet and JSP standards. However, they differ in setup, performance, deployment, and integration. Since these versions are outdated and no longer supported, upgrading to a newer release is recommended for better security, performance, and compatibility.

To better understand how server behavior impacts performance and configuration, it’s helpful to look at how Apache handles hostname lookups under different settings.

What is Apache Tomcat?

Apache Tomcat, also known as “Tomcat,” is a free, open-source web server that supports Jakarta Servlet, Jakarta Expression Language, and WebSocket technologies. It provides a pure Java HTTP environment for executing Java-based web applications. While it is not a full-fledged Java EE application server, it does provide a lightweight and effective solution for many Java web applications.

How Apache Tomcat Handles Requests

Now that the core components of Apache Tomcat are clear, let’s walk through how it processes an HTTP request. The request lifecycle involves six main steps:

• A client sends an HTTP request (usually through a web browser);
• The request first reaches a web server;
• The web server sends the request to the Tomcat container;
• Tomcat and its connections determine how to handle the request;
• The container creates an appropriate response based on the request;
• The answer is sent to the client via the web server.

The behavior of Tomcat during this process is largely defined in the server.xml file. When a Java servlet is needed, it gets initialized to handle the request. If a JSP file is involved, the Jasper engine compiles and executes the Java code behind it to produce the final output. When the answer is ready, the Coyote connection returns it to the client’s browser, completing the cycle.

Tomcat 5.0.x vs. 5.5.x: Configuration Differences

When installing web applications on Apache Tomcat, setting resources such as database connections is critical for ensuring consistent performance and data management. These configurations may be applied globally using the server.xml file or per application via the context.xml file.

To configure a JDBC resource in Tomcat 5.0.x, two items are commonly used: <Resource> and <ResourceParams>. The <Resource> element declares the resource, while <ResourceParams> defines parameters like username, password, JDBC URL, and driver class. This structure supported modular configuration but needed more verbose setup.

Example MySQL database configuration in Tomcat 5.0.x:

<Resource name=”jdbc/TestDB”

         auth=”Container”

         type=”javax.sql.DataSource”/>

<ResourceParams name=”jdbc/TestDB”>

  <parameter>

    <name>username</name>

    <value>javauser</value>

  </parameter>

  <parameter>

    <name>password</name>

    <value>javauser</value>

  </parameter>

  <parameter>

    <name>driverClassName</name>

    <value>com.mysql.jdbc.Driver</value>

  </parameter>

  <parameter>

    <name>url</name>

    <value>jdbc:mysql://localhost:3306/javatest?autoReconnect=true</value>

  </parameter>

</ResourceParams>

In Tomcat 5.5.x, this approach was deprecated. All resource parameters must now be specified directly as attributes within a single <Resource> element. Attempting to use the old format will result in configuration errors during deployment.

<Resource name=”jdbc/TestDB”

         auth=”Container”

         type=”javax.sql.DataSource”

         username=”javauser”

         password=”javadude”

         driverClassName=”com.mysql.jdbc.Driver”

         url=”jdbc:mysql://localhost:3306/javatest?autoReconnect=true”/>

When updating Tomcat from 5.0.x to 5.5.x (or later), all necessary configuration files must be updated to match the new syntax. Ignoring these changes may prevent the application from deploying correctly or disrupt database connectivity.

Apache Tomcat 5.x Archive Access and Version Overview

Apache Tomcat 5.0.x and 5.5.x are no longer supported and have reached end-of-life. Though still available in the archive, they’re outdated and not suitable for production use.

Apache Tomcat 5.0.x offered several updates over the earlier 4.1 version, including:

• Performance improvements and reduced memory usage;
• A redesigned application deployment process with a standalone deployer;
• Server monitoring via JMX and the manager web application;
• Enhanced scalability and reliability;
• More effective handling of JSP Tag Libraries;
• Better integration with Windows and Unix systems through native wrappers;
• Embedding support with JMX;
• Additional security features through an improved Security Manager;
• Built-in session clustering;
• Expanded documentation resources.

Despite these improvements, Apache Tomcat 5.x is now outdated. Users are highly encouraged to upgrade to Tomcat 9 to take advantage of current security updates, compatibility improvements, and continued support.

Apache Tomcat 5.5.x Support Has Ended

The Apache Tomcat team stated that support for Apache Tomcat 5.5.x would formally expire on September 30, 2012.

After this date:

• New releases for the 5.5.x branch are unlikely to occur;
• Reported bugs that only affect the 5.5.x version will no longer be investigated or fixed;
• Security vulnerabilities will not be reviewed in relation to the 5.5.x branch.

Following this, additional changes will take place after 31 December 2012:

• The download pages for 5.5.x will be removed from the website;
• The most recent 5.5.x release will no longer be available on official mirrors;
• The source code repository for 5.5.x will be moved from /tomcat/tc5.5.x to /tomcat/archive/tc5.5.x;
• Documentation links for 5.5.x will be taken down from the official Tomcat website;
• The related Bugzilla project will become read-only.

Although active support for Apache Tomcat 5.5.x is ended, all versions will remain available for reference and legacy usage via the archive.

Conclusion

Apache Tomcat 5.0 and 5.5 introduced several changes in deployment, configuration, and integration. Although they were widely used, both versions are now unsupported and no longer receive updates or security fixes. Using them in active projects is not recommended. For greater speed, security, and compatibility with modern technology, select a supported version like Tomcat 9 or later.