Commenting about Comments

//TODO : Finish this rant
#There has been a lot of discussions about the use of comments that appear in program code. This was something that I overlooked so far and only used when it appealed to me, which is itself a rare occasion for me.

#In the book, '97 things every programmer should know', there have been a lot of insight over the same issue. In it, Carl Evans recollects a lesson that he learned from his teacher(getting poor grades without commenting). The same thing, in fact happened to me too.

#Recently, a lecturer teaching Software Engineering (who is quite vociferous in his teachings)in our class proclaimed, “Comments are just waste of time and people(coders perhaps ?) should be kicked in their ass for writing comments. Comments indicate that the programmer was wasting time in writing them instead of writing LOCs”.
However, I learned a lesson similar to Carl in my class exams held in the previous week. In the exam, there was a question that required us to print a pascaline triangle using C#. I wrote its program, that I conjured up at the moment and hoping that it'll yield returns in terms of marks. But to my utter surprise, the program in question was awarded a big 0.
While explaining the paper, this teacher(who teaches .NET framework and C#) declared the opposite of the commenting practices listed above.
In my opinion, the amount of comment that you really need to insert is when the code requires some external prodding to be able to be understood.

So, I guess that it is probably useful to create and maintain comments in a codebase if it is self-describing. According to me, for long term basis a comment should only written specifically for technical documentation. The use of javadocs or msdn styled comments not only serve the purpose for the ordinary comments, but also aid future developers into maintaining and extending the software as they can provide insight in various ways( separate documentation and IDE support).

In The Elements of Programming Style (Computing McGraw-Hill), Kernighan and Plauger note that “a comment is of zero (or negative) value if it is wrong.”. These, alongwith my thoughts over the usability and proportionality of comments are echoed in this javaranch discussion thread. Hopefully, in the near future such a situation may not arise when it became an embarrassing situation for me, just because of lack of comments in my otherwise correctly functioning piece of code.

Why performance matters #1

One of the many issues that i've faced as an enterprise java developer has been performance. It is important to understand the issues surrounding performance and address them before the problems escalate into unresolvable issues. It is probably the fixation of architectural design patterns and conventions with the enterprise java community that lead us to overlook various performance related issues.

The community has today moved a long way from MVC frameworks and monolithic j2ee 1.4 servers to increasing adoption of various open source frameworks and protals. The enterprise applications too have evolved from websites having component based solutions to portals and coarse granular SOA applications, built on top of web services. However, one thing remains constant, that is the layered execution model of any application. This can be demonstrated as follows :

Our Java EE Application
Application Framework
Application Server
Java Runtime Environment
Operating System
Hardware

It is important to note that the performance of the solution does'nt depends on the application alone, rather, it depends on correct performance tuning and optimization of all the layers associated with the application. This form of issue is known as Vertical complexity.

In actual applications, however, there are a lot of discrete components that are present, each with its own 'stack' of complexity. Together, this forms into another complexity known as horizontal complexity. These issues are apparant only when the application faces heavy load in its lifecycle or when it begins to operate beyond a single JVM. This can result in the following problems :-

• Slow execution of application- beyond the aggreed upon threshold in SLAs
• Application performance degradation over a period of time- memory leaks, resource allocation bugs
• Erratic CPU utilization and application freezing
• Performance anomalies which occur in production- hard to reproduce, which escape load testing

So, it is not hard to imagine why organizations and teams look forward to solve the problems. Solution to these problems has also a fancy name, “Application Performance Management” which is a set of recepies and approaches meant to address the issues listed above. In development, this is applied to memory analysis, code profiling and test coverage. Memory analysis can be done using any standard debugger and most IDEs usually have a nice interface to do so. Profiling, however involves some serious investment into the profiler that you are planning to use. Fortunately, some IDEs like netbeans have in built profilers, but external profilers like yourkit are more relied upon. A code coverage tool does the same thing for performance testing as it normally does for unit testing- identifying whether a given code is covered under performace testing or not.

Returning to our 'stack' for a moment, we can easily visualize the tasks needed for performance optimization at different levels.

While the performance at application level can be done via APM, the underlying application framework also plays an important role. For instance, if the framework is in beta and the application is using some new feature of it, chances are that it might have a bug that can wreak havoc upon the application and create confusing problems. The application server also needs to be properly tuned and customized for clustering and performance scaling if needed. In other cases too, there is a need for system administration of these servers as they not only act as the host for the application, but also provide monitoring activities (which can further be used as performance measurement) and manage external resources needed by the application. JVM is an often ovelooked slice of the stack, which if used correctly, can cause precise Garbage Collection trips, memory management for the application as well as its dependencies. It never hurts to have knowledge of the JVM memory areas like stack, heap and perm spaces, which are the places where the application and its server reside and operate. The operating system and hardware are the obvious choices for performance optimization because these provide the underlying resource allocation, scalability, computation and other aspects that are needed for the software. From a developer's point of view, the operating system and hardware is not generally modifiable, but the overlying layers are. So it is better to have an understanding of these concepts. In a future post, i'll start with analyzing specific performance issues relating to a tier and post recepies and solutions that I came up with so far.

IBM Offers free System Z Mastery exam to students

The IBM System Z is a part of IBM's zEnterprise system, which combines mainframe, power and system x in a single system and as claimed by IBM, can save more than 50% in costs.
This includes z/OS, which is a widely used mainframe operating system.Today the mainframe plays a central role in the daily operations of most of the world's largest corporations. Even the advent of private and hybrid cloud has yet to impact the mainframe market significantly and as mainframes continue to evolve, the demand for professionals working on them rise.

Enough of the briefest of the introductions about this technology.
I wanted to share this information that IBM are conducting the System Z mastery exam for free (they are giving vouchers) to students by the end of this year (before 31st December 2010)
You can visit http://www.ibm.com/developerworks/university/systemz/masterytest/st... for more details.
The course materials are also included at the website.
These exams are important as they can serve as your career decider; mainframe administration is a field in itself.
Unlike configuring server systems targeted for smb s, this involves programming, monitoring, fault tolerance and scalability challenges.
Hope you have fun!

An Open Source Summer Event

We, the members of Open Source University Meetup recently conducted an on campus event this summer on 5th of July. As always, it was a successful event with a large turnout and participation of students from different years and branches.
This was an altogether a different event as compared to the few previous ones. In this event, we held discussions on how to conduct our group in future and also decided on what next things that we as an open souce lobby in our college ought to be doing.
As the markets for open source softwares continue to mature, so is the increasing number of tools, frameworks and libraries which in short, propell this phenomenon even further.

We are going to have new students coming into our college very soon in the upcoming academic year and this presents an excellent opportunity for us to reiterate and rekindle our spirit of openness and sharing. Special thanks for this time go to Gaurav, Sushant, Raghuvendra, Lalit and others for assembling everyone and making this event a sucess.

Mainly, we held brainstorming sessions on the following areas :

1. Cool Technologies that we can discuss in depth in future.
2. Promoting various Oracle based software.
3. Spreading the need of sharing and contributing in the IT industry.
4. Trying out open source technologies and helping spread its awareness and adoption.
5. Conducting events of varied themes and involving various activities- everyone in community can chip in. 

As always, by conducting these events, we continue to equipt ourselves better in the event management as well as improving upon the contents of our presentation and doing more than ever for the community.

See the event pics at my OSUM profile albums
http://osum.sun.com/photo/albums/on-campus-event-5th-july

Enterprise Ruby : First Impressions

I cannot stop marvel at the 'gem' of a useful software that I installed today (www.rubyenterpriseedition.com). As its name was enterprise ruby, earlier my impression was that it was some proprietary software (I had heard websites like twitter using it) but to a pleasant surprise, turned out to be an open source software distributed by Phusion (the same guys behind Passenger deployment tool). It is provided for all *NIX systems and ready to run .deb installer for Ubuntu.
Well, to the point itself, Enterprise Ruby features :
# An enhanced garbage collector. This allows one to reduce memory usage of Ruby on Rails applications (or any Ruby application that takes advantage of the feature) by 33% on average.
# An improved memory allocator. This increases Ruby's performance drastically.
# Various developer tools for debugging memory usage and garbage collector behaviour

A lot of this optimization is POSIX dependent, which is why there is no such version for windows yet. The FAQ page (http://www.rubyenterpriseedition.com/faq.html) demonstrated this and a lot more about the improved platform, which is why a lot of production servers are adopting it.

However, the nicest thing in the  whole installation was that you got a lot of commonly used gems installed, which is really appreciative because we otherwise have to manually install or repeatedly try to install via the gem repository (a thing that sadly fails most of the time for me).

Hopefully you find this information helpful. If you feel anything contradictory to that posted above, please do comment as I might be wrong in some areas that I haven't checked out yet.