My Tech Notes

Issue in Sonar when Analyse with Ant Task

2011-09-19T15:58:00.000+05:30

Had you install the Build Stability Plugin in Sonar and try to run the sonar anlayze( http://docs.codehaus.org/display/SONAR/Analyse+with+Ant+Task) You may Come Across a NullPointerExceptio as below.

build-sonar.xml:56: java.lang.NullPointerException

at org.sonar.plugins.buildstability.BuildStabilitySensor.getCiUrl(BuildStabilitySensor.java:60)

at org.sonar.plugins.buildstability.BuildStabilitySensor.shouldExecuteOnProject(BuildStabilitySensor.java:51)

at org.sonar.api.batch.BatchExtensionDictionnary.shouldKeep(BatchExtensionDictionnary.java:105)

at org.sonar.api.batch.BatchExtensionDictionnary.getFilteredExtensions(BatchExtensionDictionnary.java:95)

To Overcome This you need to define below ant property

<property name="sonar.build-stability.url" value="<ANY String need not to be a Valid URL"/>

I got the same issue last week and was unable to resolve the issue So I jus down load the Code for above plugin and look at it.
This is the actual root cause for this. To integrate sonar with CI Agent using sonar.build-stability.url or CiManagement of pom of the project. Pom is present only if this is a maven project. So if you don't specify the above property then it will try to load CiManagement using POM since ant projets does not have POM this will throw NullPointerException.
CiManagement ci = project.getPom().getCiManagement();

public class BuildStabilitySensor implements Sensor {
..........
..........
..........

public static final String CI_URL_PROPERTY = "sonar.build-stability.url";

..........
..........

protected String getCiUrl(Project project) {

String url = project.getConfiguration().getString(CI_URL_PROPERTY);
if (StringUtils.isNotEmpty(url)) {
return url;
}

CiManagement ci = project.getPom().getCiManagement();
if (ci != null && StringUtils.isNotEmpty(ci.getSystem()) && StringUtils.isNotEmpty(ci.getUrl())) {
return ci.getSystem() + ":" + ci.getUrl();
}
return null;

}

Automate Log testing

2011-06-03T07:55:00.000+05:30

We have automated java test cases for our project. but we never successfully automate the logging test cases because of the file size.
These logging are done using log4j and each api request has a trace-id Manually when we want to trouble shoot an issue we grep this trace-id and follow the log entries.
So what we do is rather than reading the file and get a FileInputStream we run the grep command and get the input stream of that process and do subsequent evaluation.

Process process = Runtime.getRuntime().exec(String.format("grep -m 1000 %s",traceid));
// get the input Stream of executed process
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));

Here we need to remember to specify a maximum line for grep command using -m flag otherwise this cannot be done. we can use a large value for -m to make sure we are reading all the lines.

Install and Configure Apache Tomacat 5 to run with java 1.4 SDK in Linux

2011-03-28T22:35:00.001+05:30

download apache full version from
http://archive.apache.org/dist/tomcat/tomcat-5/v5.5.17/bin/apache-tomcat-5.5.17.tar.gz
and 1.4 compatible files from
http://archive.apache.org/dist/tomcat/tomcat-5/v5.5.17/bin/apache-tomcat-5.5.17-compat.tar.gz
and copy it to the folder you want to install the tomcat server (I refer to this as APACHE_FOLDER here after.

1. Open the console
2. Go APACHE_FOLDER (cd )
3. Unzip archives
gunzip *
tar -xf apache-tomcat-5.5.17.tar
tar -xf apache-tomcat-5.5.17-compat.tar
4.set CATALINA_HOME and TOMCAT_HOME environment variables as follow
i. open the .bash_profile in home and insert following two lines
export $CATALINA_HOME=/apache-tomcat-5.5.17
export $TOMCAT_HOME=/apache-tomcat-5.5.17

To edit .bash_profile you can use vi editor. Type vi ~/.bash_profile in console. It will open .bash_profile file.
Then type i (this will go to Edit mode)
Then type above two lines in the folder then press Esc button, ( This will go to command mode )
Then type :wq and press enter ( this will save our modifications )
5.To set this variables either you have to type source ~/.bash_profile in every command prompt you open or restart the machine to make the effect permanently

“Using RESTful Web Services and Cloud Computing for Next-Generation Mobile Applications” by Jason H. Christensen.

2010-10-22T20:13:00.001+05:30

Today I listen to a video presentation on “Using RESTful Web Services and Cloud Computing for Next-Generation Mobile Applications” by Jason H. Christensen. He presents the evolution of the mobile devices over the last decade. Then He talks about Features of mobile devices f the smart phone that can be used for mobile computing; TCP application connection, Multi modal Radio Connectivity (like WI-FI, bluethooth, cellular connection) Sensors for ascertaining context and Programming Language Interface . And limitation of the mobile devices limited input, Minimal Storage, Highly constrained Processing Environment, and Poor quality of multitasking. Using Cloud computing how we can overcome these difficulties . Finally He presents some Guidelines for Using REST to implement mobile applications shows an example and some other aspects of Mobile cloud computing like Security.
This is the link for the presentation http://www.infoq.com/presentations/Mobile-Cloud-REST

The W3C QA Tools for Web Pages

2010-10-22T13:33:00.001+05:30

For Last couple of years I have been working on Web services and web sites. I started working on these projects with the impression that it is really easy to develop web pages since those do not involve complex logic. But with the experience I realized that developing UI is also an important and difficult task as much as developing the business logic. Some UI layout does not work correctly and these layouts differ from browser to browser. Still those are hard to detect through Unit testing and very few tools are developed to help identifying UI Layout. I have come across the situation where I made changes to css but web page does not display as indented and then it was a nightmare for me to identify the error with the CSS. If I fixed it to work on IE 6 it tweaks the layout in Firefox and etc... And fixing these takes as much time as the business-logic.
We may able to develop a web site with all the functional requirements and address other non-functional requirements like performance, security, fail over and robustness. But Users who are not IT professional get the first impression of the project by looking at the UI (web pages). UI development plays a very important role in Project.
Firebug was an interesting tool - plugging for Firefox - that helps me to troubleshoot UI layout bugs. But it still it does not validate the CSS file. Today I come across this site http://www.w3.org/QA/Tools/ maintain by W3C group and they have developed four interesting tool to validate bug on web pages.
* Unicorn - W3C's Unified Validator
* The MarkUp Validator - check Web documents in formats like HTML and XHTML, SVG or MathML.
* The Link Checker - Checks anchors (hyperlinks) in a HTML/XHTML document; Useful to find broken links, etc.
* The CSS Validator - validates CSS stylesheets or documents using CSS stylesheets.

I think all these are quite interesting and I should try these out in my next project to ensure the Quality of my work.

Google WebP - New Image Compress Format

2010-10-02T10:04:00.001+05:30

Google has announce a new image format WebP (pronounce weppy) to shrink the image size basically in Web Pages. This will improve the user experience on web site, reduce the bandwidth and hosting cost due to small file size. A WebP file consists of VP8 image data, and a container based on RIFF.

WebP team has performed comparative study of three image format WEbP with Jpeg 2000 and re-jpeg over a set of 1 million pages and published the results with the conclution that WebP achieves overall higher compression than either JPEG or JPEG 2000. Gains in file size minimization are particularly high for smaller images which are the most common ones found on the web.
G
oogle provide free open-source tool webpconv that convert images to from webp format .The tool currently support Linux x86 (64-bit) platform and google promise a tool for Windows as well. BMP, JPEG, PNG, WEBP can be used with this tool and user can choose the trade-off between quality and the file size by specifying the -quality parameter.
WeBP home page

Kill a task/process running in the system using Java

2008-06-11T11:46:00.001+05:30

We can use following code line to kill a process currently running in the system
Runtime.getRuntime().exec("taskkill /IM " + + " /F");
E.g. to kill internet exlporer
Runtime.getRuntime().exec("taskkill /IM " + IEXEPLORER.EXE + " /F");

Get List of tasks\Processes running in the system using java

2008-06-11T11:35:00.002+05:30

to get tasks currently running in the system we execute following command in command prompt
tasklist.exe /nh

this will gives a output like this in command line

We can execute any console command using exec method in Runtime.following lines show how to get names of the task(s)/process(es) currenlt running on the system

Process process = Runtime.getRuntime().exec("tasklist.exe /nh");
// get the input Stream of executed process
BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
// Read line by line
while ((commandline = input.readLine()) != null) {
if (!line.trim().equals("")) {
// Keep only the process name
processes.add(line.substring(0, line.indexOf(" ")));
}
}

A Changing Life: She does it all.

2008-06-09T11:44:00.001+05:30

This is a very touching story about Children in Africa. Every body should read this.A Changing Life: She does it all.

Bean Wiring in Spring

2008-05-13T21:07:00.000+05:30

In traditional programming ,creating associations between objects lead to code that is difficult to reuse and unit-test, and these objects are usually highly coupled to each-other making them hard to reuse and unit test, and they are doing more work than they should making them less cohesive.
In spring components are not responsible for managing associations with other components. Instead they are given references to collaborating components by the container. The act of creating these associations between applications is called wiring.

Spring Modules

2008-04-22T14:12:00.002+05:30

Spring Framework

2008-03-31T19:30:00.003+05:30

Spring is an open-source framework, created by Rod Johnson.It was created toaddress the complexity of enterprise application development. Spring makes itpossible to use plain-vanilla JavaBeans to achieve things that were previously onlypossible with EJBs.
Benifits of Spring Framework■ Lightweight—Spring is lightweight in terms of both size and overhead.
■ Inversion of control—Spring promotes loose coupling through a techniqueknown as inversion of control (IoC). When IoC is applied, objects are passivelygiven their dependencies instead of creating or looking for dependentobjects for themselves.
■ Aspect-oriented—Spring comes with rich support for aspect-oriented programmingthat enables cohesive development by separating applicationbusiness logic from system services
■ Container—Spring is a container in the sense that it contains and managesthe life cycle and configuration of application objects. You can configurehow your each of your beans should be created—either create one singleinstance of your bean or produce a new instance every time one is neededbased on a configurable prototype—and how they should be associatedwith each other.
■ Framework—Spring makes it possible to configure and compose complexapplications from simpler components. In Spring, application objects arecomposed declaratively, typically in an XML file. Spring also providesmuch infrastructure functionality (transaction management, persistenceframework integration, etc.), leaving the development of application logic to you.

Following Link shows a how to build a simple Spring Application
http://www.springframework.org/docs/MVC-step-by-step/Spring-MVC-step-by-step-Part-1.html
you need to download simpleLog from following link to do the above sample https://simple-log.dev.java.net/downloads.html

Location Based Services

2007-06-15T12:50:00.000+05:30

LOCATION BASED SERVICES (LBS) are emerging technology which uses information technology geographic information systems (GIS) and mobile technologies as a combination

An enormous market can be seen in this area including the market for tracking, route-finding and guiding

In contrast to Global positioning Systems (GPS) which simply provide the location of a user LBS provides application oriented location services.

E.g. shortest path from current location to destination

GIS has been mostly used for institutional purposes. Now the rapidly evolving wireless technology make it possible to apply personal productivity such as finding friends, finding current traffic conditions etc…

Pablo Neruda (July 12, 1904 – September 23, 1973),

2007-06-14T09:43:00.000+05:30

Pablo Neruda whose real name is Neftalí Ricardo Reyes Basoalto is a Chile writer and a communist politician. He spent his childhood and youth in Temuco, in Chile.

At the early age of thirteen he began to contribute some articles to the daily "La Mañana". In 1920, he became a contributor to the literary journal "Selva Austral" under the pen name of Pablo Neruda.

Between 1927 and 1935, the government put him in charge of a number of honorary consulships, which took him to Burma, Ceylon, Java, Singapore, Buenos Aires, Barcelona.In 1939, Neruda was appointed consul for the Spanish emigration
In 1943, Neruda returned to Chile, and in 1945 he was elected senator of the Republic, also joining the Communist Party of Chile. Due to his protests against President Gonzalez Videla's repressive policy against striking miners in 1947, he lived underground until he managed to escape from his country 1949. he spent next three years in exile traveling in Europe India and Soviet Russia.
He was awarded Nobel prize in 1971.Neruda died of heart failure on the evening of September 23, 1973, at the age of 69 soon after Pinochet came into Power

For more information:

http://en.wikipedia.org/wiki/Pablo_Neruda

to read his poems goto

http://www.poemhunter.com/pablo-neruda/

John Stuart Mill (20 May 1806 – 8 May 1873)

2007-06-12T16:16:00.000+05:30

J. S. Mill was a British philosopher, political economist and Member of Parliament, was an influential liberal thinker of the 19th century.
he was an independent Member of Parliament, representing the City and Westminster constituency from 1865 to 1868.
During his time as an MP, Mill advocated easing the burdens on Ireland, and became the first person in Parliament to call for women to be given the right to vote.
Mill's moral philosophy was a modified version of the utilitarian theory he had learned from his father and his god father Jeremy Bentham.
Mill became a strong advocate of women's rights and such political and social reforms as proportional representation, labor unions, and farm cooperatives. In 1869, he argued for the right of women to vote. He was godfather to Bertrand Russell.
In 1851 he married Harriet Taylor after 21 years of intimate Friendship

Taylor died in 1858 after developing severe lung congestion, only seven years into her marriage to Mill.

He died in Avignon, France in 1873, and is buried alongside his wife.

Mill argued,If society really wanted to discover what is truly natural in gender relations it should establish a free market for all of the services women perform, ensuring a fair economic return for their contributions to the general welfare. Only then would their practical choices be likely to reflect their genuine interests and abilities.

both of them have written an essay called "The Subjection of Women" stating an argument in favour of equality betweeen the sexes

eventhough it seems as a essay on feminism it is not , it is clearly utilitarian argument .

WHITE ROSE PAPERS

2007-06-11T12:45:00.000+05:30

Almost every body in this world knows about Hitler was the German Chancellor from 1933 to 1945 and Führer of Germany from 1934 until 1945. He was also the leader of the National Socialist German Workers Party (Nationalsozialistische Deutsche Arbeiterpartei simply Nazi Party) and is considered the effective founder of Nazism.

But very few Know about the group "White Rose" , the group that stood behind the first and the last spontanic revel in the days of the reich was burst in 1943.

The group acted in the university of Munich and its main leaders was three anti-nazi and idealist students: Hans Scholl, Christof Probst and Alex Schmorell- medicine students, and Sophie Scholl, Hans' sister that studied philosophy and biology.

Not like the main resistance movement, their activities were hopeless, but they sure proved great heroism and courage among the group's members.

In the summer of 1942 they wrote four leaflets, and they left them in many places. The leaflets were dropped in public telephone cabins and mailed to students and professors all over Germany. In this way, the anti-nazi ideas was spread in universities all over the country. Some leaflets found their way to the gestapo, and the secret police started to wonder about their source. The students that carried the leaflets to different places in train just "hoped for the best". In any case, the problem was solved in an interesting way. The leaflets were given to female students, who were less checked by the gestapo.

The leaflets that was written by the group were titled as the "leaves of the white rose". They attacked the nazi regime and mentioned its crimes, from the mass extermination of jews and the murder of the Polish nobility and intellectual elite, to the dictatorship and the elimination of the personal freedom of the German people. The leaflets contained quotes from great philosophers and writers like Goethe, Nobalis, Aristotle and Law Tso, and they were written in a very high level. It was clear that they were written to intellectual public, and especially to students and professors.

Why those small leaflet are so important ? in a era where no body speak about truth afraid of their lives acted blindly towards ruthless governments.

These people are a great example for our lives who only think of doing a good job , having a settled family life. They pay for this activity by their lives. Even though they live for ever.

Rosa Luxemburg (1871-1919)

2007-06-08T10:11:00.001+05:30

Rosa Luxemburg was a German revolutionary leader, journalist, and socialist theorist, who was killed in Berlin in 1919 during the German revolution. Rosa Luxemburg saw herself as a citizen of the proletariat. She lived the international life of a Socialist 'pilgrim', believing that only socialism could bring true freedom and social justice. Luxemburg was the advocate of mass action, spontaneity, and workers democracy.

Reevaluation of Luxemburg's work started in Germany in the 1970s. Apart from her works regarding Marxism her theories which is considered to be a alternative to communism or Social Democracy,Luxemburg arose still interest among feminist theorist.

Luxemburg herself did not participate into women's rights movement; women's liberation was for her part of the liberation from the oppression of capitalism. However, she saw that socialist emancipation is incomplete without women's emancipation.