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Connecting Apache and Tomcat using mod_jk

Aim of the Task: Connect Apache Http Server 2.0.63 with Tomcat 5.5

My Apache is running at 80 and Tomcat running at 8080. I have an application running in tomcat at url http://localhost:8080/examples and after this configuration I should be able to access the application through Apache.

1) Download mod_jk

Download the mod_jk module from the following location.

http://www.apache.org/dist/tomcat/tomcat-connectors/jk/binaries/win32/jk-1.2.27/mod_jk-1.2.27-httpd-2.0.63.so 

Copy this file to Apache modules directory.

2) Create worker.properties

Create worker.properties in the Apache conf directory and paste the following default content in it.

# Define 1 real worker using ajp13

worker.list=worker1

# Set properties for worker1 (ajp13)

worker.worker1.type=ajp13

worker.worker1.host=localhost

worker.worker1.port=8009

3) Generate mod_jk.conf

This file is auto generated by the Tomcat. Add the following line in the server.xml of Tomcat under the <Server> root tag.

<Listener className="org.apache.jk.config.ApacheConfig" modJk="APACHE_INSTALL_DIR/modules/mod_jk-1.2.27-httpd-2.0.63.so" workersConfig="APACHE_INSTALL_DIR/conf/workers.properties" />

Note: Replace APACHE_INSTALL_DIR with the complete location of the Apache Installation Directory.

Start the tomcat server and if everything is ok then Tomcat will generate the mod_jk.conf under the directory Tomcat5.5/conf/auto.

4) Modify httpd.conf

Now open the httpd.conf file and load this conf. 

Include tomcat-5.5/conf/auto/mod_jk.conf

5) Configure Tomcat applications for Apache

Add the following lines to configure how Apache uses JK module.

# Send everything for context /examples to worker named worker1 (ajp13)

JkMount  /examples/* worker1

DONE. 

Now start Apache and access the examples url without port. Ex: http://localhost/examples

Tech Jargon - 16 Dec 2008

• Content Delivery Network - A network of Servers delivering cached content (generally images, flash and scripts) to improve performance of a site.
  
  
• Akamai - A leading CDN company providing services to comapnies like SONY, Yahoo and Microsoft.
  
  
• Embryonic Connection - A TCP connection which is not completely established.
  
  
• Terracotta - is an open source JVM-level clustering software for Java. It delivers clustering as a runtime infrastructure service, which simplifies the task of clustering a Java application immensely, by effectively clustering the JVM underneath the application, instead of clustering the application itself.
  

ArrayList ClassCastException

When trying to typecast Object array to the Actual array type, a runtime ClassCastException is thrown.

ArrayList lst = new ArrayList();
lst.add("String 1");
lst.add("String 2");
lst.add("String 3");

String[] strArr = (String[])lst.toArray();


Solution for this is to use the toArray method with argument.

String[] strArr = new String[0];
strArr = (String[]) lst.toArray(strArr);