Using JMX

JMX is an integral part of J2EE but mostly neglected compared to other aspects. Here's some practical learnings.

Understanding
JMX is used to manage your application (or even the application server). It's a very simple 3-step process.

1. You write your Management Beans or MBeans to provide the management functionality.
2. Then your register your MBean with the MBean Agent (MBean Server).
3. Now you can manage your application by connecting to the MBean Server and calling the required functionality.

When to use
The decision of when to forgo the use of configuration files and code to update settings and when to use JMX is not clear-cut. It's definitely a better idea when program management forms a larger part since JMX is very scalable. But I think JMX is an even better idea when you have limited managment requirements and don't want to add a custom user interface module just for the management. In this case, JMX allows you to provide the neccessary interface with just 10 lines of code and use of the ubiquitous JConsole to do the agent connection (see my Using JConsole to connect to an MBeanServer post on how to use JConsole for this).

Must have tools for the Smart Java Professional

Whether it's planning, design, development, reviewing, testing or tuning, there's a wealth of wonderful free (or nearly!) tools out there for the Java professional. It's not like all of them will be useful all the time... but its one of those things you should be knowing. No one wants to be in the situation of having a flat on a lonely highway and not knowing how to change the tire. It really helps to practice and familiarise with certain necessities even though you may not use them everyday.

Here's a list of my favourite tools (I'll stick to free / open-source) which I consider every Java professional should have in reaching distance. I will keep updating this post with useful Java tools - may add separate detailed posts for complex tools... would welcome any suggestions to update this list.

IDE
There are plenty of excellent Java Editors and this is what most beginners are encouraged to start with. But I think other than the geek-appeal, a more proficient Java professional should use a full-featured Integrated Development Environment (IDE) - don't give excuses like having to use one more program instead of your all-in-one editor is a pain, or that your IDEs hog your system (come on, you shouldn't be coding if your system is that slow!).
My favourite IDE is Eclipse - it's latest Ganymede release has different packages based on your usage - Java EE Developer, Java Developer, C/C++ Developer, etc, or just get Eclipse Classic.
Other IDEs (all with J2EE development features):
NetBeans - used to be very slow but I'm seeing a LOT OF good reviews about it now!
Oracle JDeveloper - supposed to be ok
IBM WebSphere Studio Site Developer - it's not limited to WebSphere Server btw
WebLogic Workshop - seems to tie you to the Weblogic Server, although that too comes along in the Free version
In general, the trend is love one and hate the rest! So choose wisely...

Security
This is a highly neglected area even though it is most fundamental part of any application especially as we go into the future. My one stop site for this is the Open Web Application Security Project website - Enterprise Security API (ESAPI) & Antisamy are available there. Also see my detailed post on Antisamy.

Code Review
Always ensure any code you touch, whether yours or not, gets time to go through a couple of code review tools. In the heat of reaching a target, developers just can't help taking shortcuts that result in code that can be caught in review tools and some of these mistakes can lead to major headaches at some point or the other.
Some of the common review tools include FindBugs, HammurAPI & CheckStyle. I got some nice feedback for JLint & PMD but I haven't tried them out. Both of these work purely on your source so they are really fast - whereas the other tools actually go through your generated class files and hence would catch logical or even runtime errors.
I should mention that no single review tool does a complete job - when it's upto me, I usually go for a combination of Checkstyle and FindBugs.

One more useful software is an Eclipse plugin called Metrics. This shows minute details of your code including a very good graphical representation of package dependency.

Code Testing
JUnit is the way to go for me but for J2EE applications, Cactus (which extends JUnit) is more suitable if you can stand the complexity. Also, there's Webtest to test interactions with your Web Application.

Code Coverage
EMMA comes to mind as the most comprehensive free tool for this. Emma ensure that there is no unused or poorly used code in use. It can also be used to verify that your Unit Test cases were complete.

User Interface Development
We already know all about the many Frameworks that ultimately give WYSIWYG plugins for our favourite IDE. Here's something different - Metawidget is a 'smart User Interface widget' that populates itself, at runtime, with UI components to match the properties of your business objects - it builds on your underlying framework and so is not competing with it.

Version Control
This doesn't really come in the category of a developer but just listing it to be complete - CVS and Subversion. See here for a good tutorial on how to use these.


HTTP Analyser
OpenScarab: Simple powerful small Java app that inspects all http traffic and shows full request response details - also allows you to tamper inject data... OpenSource, Java

Last Updated: 22-Oct-2010

Macro to fetch email addresses for a list of names from Exchange server

I came across an interesting problem the other day... one of my colleagues had left our firm in a hurry. But she wanted to send a farewell mail to all her colleagues - she'd got a list of names by copying the names in the "To" list from a mail opened in her office Outlook. However, these were only names (as they existed in our Exchange Server) and did not contain the actual email address.

I thought it was a simple thing to give her the email address list corresponding to those names right from my Outlook window... but after a frustrating 60 mins of trying all possible combinations, I had to accept defeat.

Instead, I made a little macro that does the job - just provide the list of names as on the exchange server, and it will fill the next column with the email addreses. Download the Excel sheet having macro here .. Check out the Readme worksheet for instructions.

Note: PREREQUISITE
You should have a signed-in session with Outlook connected to your Exchange server before running the macro.

For those who are curious about how it works, the code simply accesses the Global Address List of your exchange server through your signed in Outlook account, fetches the usernames (cn values from the exchange directory) and then manually appends the company domain (this is configurable) to it. Of course it won't work for those with multiple company domains... You can check out the code in the macro's section of the excel sheet (press Alt-F11 after opening the excel sheet).

For more robust handling like getting the correct whole smtp address (instead of appending the domain manually) is possible but it would entail using extended MAPI (lots n lots of code) or extra libraries CDO / Redemption with C++.

But VBA suits my purpose. And that's what good software is all about - meeting the need (not the wants)!