Context root of single war's web applicaton in JBoss

Context root of web application is usually specifiedin META-INF/application.xml in ear file (or a vendor specific jboss-web.xml inside war ) e.g.

...
  <module>
    <web>
      <web-uri>app.war</web-uri>
      <context-root>/jsfejb3<context-root>
    </web>
  </module>
..

However if we drop a single war file without vendor specific descriptor (jboss-web.xml) into JBoss deploy directory then context root is implicitly the name of the war file without extension.
e.g.
Web application jmx-console residing in default/deploy/jmx-console.war has context root jmx-console
Web application groovy-scripts residing in default/deploy/groovy-script.war has context root groovy-script and can be accessible via http://localhost:7080/groovy-script

Centralized Management Tools

Nagios
Big Brother
Hyperic HQ
JOPR
@ctiveFriend
OEM
OpenNMS
There is a great presentation of monitoring tools here

Testing JOPR 2.2.0 - Basic configuration

Modify JBoss server startup options to include JVM as child resource of JBoss Server in JOPR

#$JBOSS_HOME/bin/run.conf
JAVA_OPTS="$JAVA_OPTS -Djboss.platform.mbeanserver"

Remove an uninterested resource from management a.k.a uninventory
Browse Resources->Servers, select uninterested one, hit uninventory button

Testing JOPR 2.2.0 - Installation

What is JOPR, RHQ, JBoss ON
JOPR is an open source project from Redhat to develop complex management platform. JOPR is agent based JAVA/J2EE system, where agent is standalone JAVA running and server runs on top of JBOSS Application Server(AS). It can be used to manage JBOSS AS, Tomcat, Apache as well as Oracle, and any IT resources.

JBoss Operations Network (JBoss ON) is commercial offer of JOPR in form of support service by Redhat.

JOPR is developed on top of RHQ project. RHQ serves as an maven upstream project for JOPR. RHQ consists of GUI management console, agent container and a set of agent plugins for management of common IT resources.
JOPR extends RHQ by adding additional plugins for JBoss App Server, Tomcat Web Server, etc. . JOPR version 2.2.0 is corresponding with RHQ version 1.2.0.

The original of RHQ is Hyperic HQ. Redhat and Hyperic work together to extract common reusable parts of Hyperic HQ and maintain it as RHQ. The aim is to create a common infrastructure for developing management's application. That is why the project named RHQ, where R stand for Redhat.

Install JOPR Server
Download JOPR binary from JOPR website
Follow instruction in Installation Guide to prepare database server for JOPR server
Change working directory to jopr-server-2.2.0 and type

bin/rhq-server.sh start

then open web browser and point to http://localhost:7080
Follow instructions in screen to set database driver, url, username/password to correct values. After that verify database connection.
Hit button Install JOPR server to complete installation process

Modify JOPR server properties file for agent communication
Modify rhq-server.properties file

# jopr-server-2.2.0/bin/rhq-server.properties
rhq.communications.connector.transport=servlet
rhq.communications.connector.bind-address=<jopr-server-ip-address>
rhq.communications.connector.bind-port=7080

Restart JOPR server

bin/rhq-server.sh stop
bin/rhq-server.sh start

Login to JOPR console and watch its log file
Pointing Web browser to http://localhost:7080/Dashboard.do
Login use default rhqadmin/rhqadmin as initial username/password
JOPR log file is located in jopr-server-2.2.0/logs/rhq-server-log4j.log

Install JOPR Agent
This shall be done in all machines that we want JOPR to manage .
Download agent from http://<jopr-server-hostname>:7080/agentupdate/download
Install JOPR Agent by typing

java -jar rhq-enterprise-agent-1.2.0.jar --install

Modify JOPR Agent configuration file

#rhq-agent/conf/agent-configuration.xml

# ask jopr agent not to ask for configuration during startup
<entry key="rhq.agent.configuration-setup-flag" value="true" />

<entry key="rhq.agent.name" value="<jopr-agent-hostname>"/>

<entry key="rhq.agent.server.bind-address" value="<jopr-server-ip-address>" />

# ask jopr agent to listen to on particular ip
<entry key="rhq.communications.connector.bind-address" value="<jopr-agent-ip-address>" />

Start RHQ Agent and watch its log file
change working directory to rhq-agent and run

bin/rhq-agent.sh -c conf/agent-configuration.xml 

If we reinstall JOPR server then agent's local data and server'data is not in sync. In that case we shall ask agent to clean it's local data when start by using

bin/rhq-agent.sh -l -c conf/agent-configuration.xml 

The most recent agent's log file is located in rhq-agent/logs/agent.log

Develop an international career - Recruiters

Recruiters (a.k.a Head Hunters) play a vital role in the job market. Many big companies use services of recruiters when they need to hire someone (they do not recruit directly). I myself and a lot of my colleagues got a job by a recruiter.
Below is a list of the most well known recruiters
- Robert Half
- Robert Walters
- Hays
- Wall Street
- Hudson
There are many smaller but also very good recruiters, who are constantly looking for a good candidate in all countries over the world. If you are somehow visible and your skill fit a opening position, they will contact you.
I got my first job via placement of a smaller recruiter named Juno located in New York.

JBoss resources

JBOSS configuration and tunning articles from Master the Boss
Running Multi JBoss Instances
Good examples of EJB 2.1, EJB 3 from Learn Technology
JBoss Official Docs & Examples from Redhat
JBoss Operation Network (ON), a.k.a JOPR - Documents
JBoss ON - FAQ
RHQ project, upon it JOPR depends
JOPR project
A blog on RHQ, JOPR, JBoss ON

Develop an international career - Make yourself visible

No matter how good and skilled you are,it is useless if no one know about it. So make yourself visible, post your resume to professional websites and social networks, create your own blog, subscribe to interested user groups, participate in an online discussion.
Keep in mind that all these techniques only work if you keep your data up to date. When a recruiter doing executive search and find your resume within dozens of others,he/she will easily exclude you if your resume is 2 years old.

Few years back I created my blog. It has only professional content and I decided to keep it in English because my intention is not to have many readers but the right one. Those are recruiters, potential employers and colleagues. I believe, that it helps me to get my first and also second job. Looking at site analytic of the blog, I don't see much traffic but I can identify those coming from area where I received a job offer or where my recruiter is located.

Linked In is great social networking site for professionals, so I would recommend to register and put your career information there.

Again, don't expect anything happened over night, it will take time.

Develop an international career - Resume

This post is created (based on my own experiences) for people who want to work out of their home countries and therefore develop their career internationally. It can be used as an advice.
You have generally only one career, so don't let it goes based on some unexpected events. If you really want to work abroad in developed countries, be prepared that it will take time to get a job. It can be two years or more depending on many factors. During this time, you may need take many actions to move into that direction.

Resume (a.k.a CV) is your ticket for entering job market. Write your resume with care and update it gradually and of course it should be in English. During last few years, I spend many hours to re-write many time my resume as well as to ask friends, colleagues and career's adviser for my resume's correction. I have to admit that I am still not satisfied with my resume as there is a lot of things to improve.

I also spend time to read resume of others, who work in the same industries and/or share a similar knowledge and career path. It help me a lot to get know how others present themselves, so I can adjust my resume to highlight my strength.

Java Class Loader's links

Impala blog post - Thread Context Class Loader
Java World - Class Loader article
On Java - Internals of Java Class Loading
Advanced JBoss Class Loading
Equinox OSGi Context Class Loader Enhancements

My resume - LANGUAGE

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• Vietnamese, English, Czech