Category: Java

Premature optimization is the root of all evil - not only in the Agile world

October 9, 2008 by pbielicki

Picture courtesy of gutter@flickr

I was just reading an excellent book by Josh Bloch, namely "Effective Java, Second Edition" and I was on the optimization subject when it happened. It was funny coincidence but I think it was just a sign for me to write this post.

It doesn't relate to the Agility in any way but it relates to the quality of software so it should be definitely published here. And it all started very innocently - from publishing blog post with the solution to some annoying problem.

In this post I will tell you how easily you can fall into really dangerous and ugly development problems starting optimizing your software too early. I hope you will like the story.

Maven supports JAR Hell

August 7, 2008 by pbielicki

In one of my previous post I wrote that using development frameworks pays off and it is generally worth investing your time in learning how to use them. I was also clear that learning process is not easy and you could lose some hair from your head or simply go mad.

I would like to present an example how easily you can get lost using Spring Framework together with Struts 2 and Maven. The problem I'm going to present is often referred as a JAR Hell. I will present ideas how to cope with that.

Code coverage: a tool against unused and untested code

July 3, 2008 by pbielicki

I'm an agile developer because I write my code incrementally i.e. only what I need today. I usually start writing the code by writing Unit Test - it really works and it really helps me understand what should be implemented and how system should behave (I will leave the subject of convincing people, who are new to unit testing, to do "write-test-first" for a separate post). OK - I usually do this but sometimes it's difficult or I'm just too impatient to see the result and start with the implementation and write unit test later. How do I know which packages/classes/methods are tested and which are "not touched" by any single unit test? How do I know that my code is really used somewhere by other parts of the developed system? This is the work for code coverage tool.

When unit testing is not enough

June 19, 2008 by pbielicki

I'd like to share my experiences about unit testing (using JUnit) Java servlets outside of the servlet container. Agile world tells us that we should automate as much tests as we can - it would be good if all aspects of the developed system are completely tested. We should test functional as well as non-functional requirements of our systems. But can all tests be automated? What is the REAL value of such tests? The reality brings us problems and pitfalls even experienced developers fall into. I will present such story regarding automated and manual testing of Java servlets.

The problem
Quite recently I had do develop some "proxy" servlets facilitating Ajax request from web browser to our middleware layer. We couldn't directly send Ajax requests because JavaScript security model doesn't allow to request data from other address than it was originally downloaded (similar restriction to Java Applet).

All right then, our servlets were not doing any amazing job (some input and output transformations were needed, however) but I made some bugs even having 100% test code coverage (used Cobertura 1.9).