my thought of week..

"The greatest pleasure in my life is doing what people say I cannot do."

Current Status

Working in a telco and perform many interesting tasks
on System developments.

Current Readings...

13 January, 2016

14 December, 2015

24 July, 2015

Test-Driven Development

It is important to understand the TDD life-cycle.

  1. Write the test
  2. Run the test (there is no implementation code, test does not pass)
  3. Write just enough implementation code to make the test pass
  4. Run all tests (tests pass)
  5. Refactor
  6. Repeat

Test-driven development is not about testing. Test-driven development is about development (and design), specifically improving the quality and design of code. The resulting unit tests are just an extremely useful by-product.

11 June, 2015

Interviewing Programmers

Hello my dear senior friends in SW engineering , how do  you interview new recruits for programming ?Do you start with phone interview and continue on written tests to face-to-face interview? Eventually it will come down to your experience and gut feeling? Most of times we do it in that way. But we have experienced some best practices of picking "better" programmers!

In an environment like work we need more “practical programmers” than just “good coders”. Because most of times our programmers will need to directly work with end user and understand the requirement from business perspective. So we have more responsibility to choose “right” people from interviews.

We take advantage of intern programs, we hunt down the smart CS/IT students and individually ask them to apply for an internship with us, because if you wait around to see who sends you a resume, you're already missing out.

In one incident tried asking applicant to develop a program, I have used a very general requirement, which doesn't need any domain expertise (telco), but require some programming experience. I normally ask to write mathematical method to calculate something, instead of expecting the programmer to do what I think should be done implicitly, what would be a better indicator in my opinion is to see how the s/he tries to ask questions on the scope of the program, purpose, usage and limitations explicitly. Unless the programmer is very familiar with the purpose of the program, he/she should not assume what is not stated, but should try to elicit them. Also I would like to try asking to write a function using basic formations related to String in Java. This is rather simpler one but ask them to write a production like code and then see if it takes care of obvious things like null string, empty string etc.

For them it's an opportunity to show their think deep ability and how good they are in understanding requirements and finding gaps. This tips are not hard and fast rules to find good programmers, in fact there are no rules to find them. You just have to work through some indicator and your gut feeling. Let me know what are the tips you guys are using to find good programmers on interviews. Please comment. 

21 November, 2014

How to convert an String into int value

There are many ways to convert an String into Integer object in Java e.g. Integer.valueOf(), new Integer(), Integer.parseInt() or writing your own algorithm to convert string to int etc, but which one is the best tool for the job.

here are different ways of converting String object into int or Integer in Java :

1) By using Intger.parseInt(String string-to-be-converted) method
This is my preferred way of converting an String to int in Java, Extremely easy and most flexible way of converting String to Integer. Let see an example of String to int conversion:

 //using Integer.parseInt
 int i = Integer.parseInt("123");
 System.out.println("i: " + i);

Integer.parseInt() method will throw NumberFormatException if String provided is not a proper number. Same technique can be used to convert other data type like float and Double to String in Java. Java API provides static methods like Float.parseFloat() and Double.parseDouble() to perform data type conversion.

2) Integer.valueOf() method
There is another way of converting String into Integer which was hidden to me for long time mostly because I was satisfied with Integer.parseInt() method. This is an example of Factory method design pattern in Java and known as Integer.valueOf(), this is also a static method like main and can be used as utility for string to int conversion. Let’s see an example of using Integer.valueOf() to convert String into int in java.

//How to convert numeric string = "000000081" into Integer value = 81
int i = Integer.parseInt("000000081");
System.out.println("i: " + i);

It will ignore the leading zeros and convert the string into int. This method also throws NumberFormatException if string provided does not represent actual number. Another interesting point about static valueOf() method is that it is used to create instance of wrapper class during Autoboxing in Java and can cause subtle issues while comparing primitive to Object e.g. int to Integer using equality operator (==),  because caches Integer instance in the range -128 to 127.

18 August, 2014


"What is this SOA?" Have you ever questioned this? many of my non-IT colleagues ask me this. So here I will word it in very simple style.

Actually, SOA is architecture style.. It is an approach you follow when you develop some systems or integrated software.

From my personal experience I would say, applying SOA in Big Bang is bad, think big, start small.

Our target should be to build SOBA(service oriented business applications)

SOA governance is the key to have service catalog.

We have to have Service bus to avoid point to point interaction.

15 August, 2014

Java Design Pattern training by Oracle

I attended a training conducted by Oracle University for "Java Design Pattern Ed 1 PRV"

10 July, 2014

Ingiriya to Gelanigama - The Ratnapura expressway

The proposed Ratnapura expressway is to be constructed between Pelmadulla to Ingiriya and it would be connected to the Southern expressway’s Gelanigama interchange through the existing highway at Ingiriya, said Ports and Highways Deputy Minister Nirmala Kothalawala. 

According to the official news portal of the government, the minister made this statement while attending the Ratnapura District development meeting held recently.

The expressway, which is to be named the “Ruwanpura Expressway,” will span across 71 kilometers.

Minister Senevirathne says that motorists traveling will be able to reach Pelmadulla within an hour via Moragahahena, Handapangoda, Horana, Ingiriya and Kiriella.

 Highway from Ratnapura to Pelmadulla, highway in Ratnapura, Minister W.D.J. Seneviratne, New highway, Ratnapura highway

24 May, 2014

Java Performance Tuning and Optimization

I just followed a course from Oracle University, Course Name:  “Java Performance Tuning and Optimization Ed 1”

Fine! It was a 3 full day course, learnt a lot. I thought to share some of with you guys. Learnt to blend tuning methodology, performance theory and practical tips on solving difficult performance problems for Java applications. Had an opportunity to hone on a series of labs derived from real performance tuning issues.. they all were well organized.  also learnt about various tools and mechanisms for monitoring, profiling and tuning Java applications.

In the first discussion on Application performance I started to believe that “Speed up” ( speeding app in same infrastructure) comes before “Scale up” (vertical scalability like add more memory..) or “Scale out”(horizontal scalability like adding new server..).

When it comes to performance tuning in an app server you should keep in mind known theory of that separate JVM is created for each Java application.

What you understand by “performance”? to me, it is basically “Responsiveness” and “Throughput” of an application. If it is an user interactive app(web or game) we need high responsiveness where we need high throughput from an server side batch processing app.

The approach for tuning(performance) a java application is Monitor> then Profile > and finally Tune!