tag:blogger.com,1999:blog-226348782026-06-04T13:21:38.521+05:30This blog mainly contains technical stuff. It may contain info of some events too.kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.comBlogger37125tag:blogger.com,1999:blog-22634878.post-13685084296615780382018-02-08T03:34:00.000+05:302018-02-08T21:27:36.389+05:30

Functional programming in Java, a useful feature was introduced with Java 8 (java.util.function package). With that, we have the ability to define a function, pass functions to a method as arguments or use already defined methods as functions. I'll use a simple example to explain a function. Function myFunction = n -> n * n   I have defined a function here, named as "myFunction". It

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com65tag:blogger.com,1999:blog-22634878.post-79542149236593159672011-08-13T00:21:00.002+05:302018-02-08T02:56:32.992+05:30

If you know how to create an installer using NSIS, you'll probably want to know how to create the uninstaller too :) So you have to write a section named "Uninstall" inside your .nsi script file. section "Uninstall" SetShellVarContext all Delete "$DESKTOP\Your Application.lnk" RMDir /r "$SMPROGRAMS\YourApp" RMDir /r "$INSTDIR" Delete $INSTDIR\uninstall.exe DeleteRegKey HKLM "

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com10tag:blogger.com,1999:blog-22634878.post-29109069512019873652011-07-15T22:41:00.004+05:302011-07-15T23:28:51.817+05:30

Sometimes you may want to embed some other installer in your installer. As an example if you need Java as a prerequisite then you can embed Java installation inside your installer. Then it will run the Java installation before installing your application, when you run your installer.  So let's write a section to embed JRE installer in your installer Section "jre" SECJRE File "

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com4tag:blogger.com,1999:blog-22634878.post-38628032073989212272011-04-28T21:07:00.020+05:302011-04-28T23:38:52.564+05:30

While writing my installer I wanted to install JRE (embed JRE installer in my installer) only if Java is not installed already. So I had to detect whether Java is already installed. My previous post on NSIS points to a quick start guide (in Harshani's blog) for NSIS, including how to install NSIS and how to write a simple installer. So at this point you should have installed NSIS and been

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com17tag:blogger.com,1999:blog-22634878.post-90802899265586688672011-04-15T00:55:00.005+05:302011-04-26T20:10:39.302+05:30

I wanted to write an installation for IFRI data entry application which is currently being used to enter forest data to their database. The existing installation had some inconsistencies like users had to install the other required software themselves, some permission issues etc. So I had to search for a pretty stable installation system with all those features I wanted. While searching I found

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com7tag:blogger.com,1999:blog-22634878.post-32148152418429864002010-10-18T20:21:00.009+05:302010-10-18T20:54:37.785+05:30

javax.print package is available in JDKs 1.4 and above. Formerly Java AWT printing API was used to perform basic printing and now it is enhanced with advanced options like printer service discovery, in javax.print API. I am posting a simple example showing how to perform a basic print using javax.print API. import java.io.*; import javax.print.*; public class PrintTest { public static void

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com14tag:blogger.com,1999:blog-22634878.post-91610684160400736602010-09-06T23:05:00.002+05:302010-09-06T23:06:40.575+05:30

I found a nice site to fetch mp3s from YouTube videos. The process is pretty simple and fast. Check it out, you'd love it.

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com12tag:blogger.com,1999:blog-22634878.post-29421005236778794312010-08-14T00:20:00.001+05:302010-08-14T00:21:20.570+05:30

netstat -ab shows which process runs on which port. If you need to find a process which runs on a particular port, the command can be used as follows netstat -ab | find ":8080 "

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com4tag:blogger.com,1999:blog-22634878.post-42985633745179922352010-08-10T02:08:00.002+05:302010-08-14T00:20:44.861+05:30

I wanted to delete some duplicate records from a table. "Duplicate" doesn't mean identical records in this scenario. I wanted to check whether the values in a subset of columns are identical and if so, to remove additional records keeping just one record in the table.  Let's assume we have a table called Person like below IdNameAgeCity 10Sunil24Matara 11Sandun25Colombo 12Nimali23Matara

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com5tag:blogger.com,1999:blog-22634878.post-62490191109756293572010-02-27T13:14:00.007+05:302011-09-07T21:01:06.055+05:30

My previous post shows how to split an image into chunks. Now let's see how to merge multiple images into one image. Say we need to concatenate following four image chunks. I got these chunks by splitting the image in the right hand side, using the image splitter.   Following code shows how to concatenate the image chunks above into one image. int rows = 2; //we assume the

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com62tag:blogger.com,1999:blog-22634878.post-62260516248014181122010-02-24T04:02:00.007+05:302010-02-24T04:16:38.102+05:30

Image splitting and concatenating and other image manipulation techniques are important in parallel computing. Say we are receiving small chunks of an Image which is being manipulated parallely. In such scenarios, we need to concatenate those chunks together and vice versa. There is a pretty straight forward way to split an image using Java imageio package. Say you need to split following image

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com386tag:blogger.com,1999:blog-22634878.post-5230640768277045802010-01-12T01:24:00.015+05:302010-01-14T20:55:19.353+05:30

A custom class loader is needed when the developer needs to load classes from some custom repositories, to implement hot deployment features and to allow unloading of classes. According to Java2 class loading system, a custom class loader should subclass java.lang.ClassLoader and overrride findClass() method which is responsible for loading the class bytes and returning a defined class.

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com33tag:blogger.com,1999:blog-22634878.post-53185650715797548022009-11-09T00:10:00.001+05:302009-11-09T00:11:40.235+05:30

I found a nice blog post explaining how to install Syntaxhighlighter code plugin to blogger. It is very simple and works great. Some additions 1. If your browser is Firefox, you should add the styles manually     * copy the stylesheet at the location http://syntaxhighlighter.googlecode.com/svn/trunk/Styles/SyntaxHighlighter.css     * Go to Layout --> Edit HTML &

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com8tag:blogger.com,1999:blog-22634878.post-62797591731040015152009-11-04T22:22:00.020+05:302009-11-05T02:50:31.685+05:30

Plotting a moving graph is nothing other than plotting an instance of a varying data set at each refresh. However, to get the moving effect you need to change the data set as stated below 1. Discard the leftmost Y value of the previous step 2. Shift the remaining Y values to the left 3. Add the new coming value as the rightmost Y value Flot is an opensource Javascript

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com10tag:blogger.com,1999:blog-22634878.post-89640686312681252602009-06-16T21:55:00.003+05:302009-11-05T07:37:15.683+05:30

I was working on a program which makes several requests to Abdera back end from the client. The client was designed to use a new AbderaClient per request and teardown method was not used on AbderaClient instance after using. This led to an exception when I run it concurrently (by using about 100 threads). AbderaClient uses HTTPClient and MultiThreadedHttpConnectionManager. Teardown method is the

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com2tag:blogger.com,1999:blog-22634878.post-90701650479838172192009-02-28T20:52:00.001+05:302009-03-02T16:40:51.573+05:30

Here is a cool midi to mp3 converter which is so simple and user friendly. Direct MIDI to MP3 Converter 5.0

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com5tag:blogger.com,1999:blog-22634878.post-86042342483580055862009-02-18T16:52:00.004+05:302009-02-20T13:31:17.650+05:30

WSO2 Carbon is the industry's first fully componentized SOA platform. It is built on OSGi. Other WSO2 products such as WSO2Registry, WSO2 Enterprise Service Bus (ESB), WSO2 Web Services Application Server (WSAS) and WSO2 Business Process Server (BPS) are Carbon based.Why Carbon? This e book says it all.

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com4tag:blogger.com,1999:blog-22634878.post-74388875809728971582009-02-10T12:12:00.006+05:302009-02-20T13:32:14.710+05:30

WSO2 Registry is a user friendly resource management solution available under Apache2 license. The new release of WSO2Registry is based on WSO2Carbon, which is meant to be the first fully componentized SOA framework in the industry.As the new release of WSO2Registry is based on Carbon, it uses a unified GUI which supports other carbon components too. Another new feature included to the 2.0

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com2tag:blogger.com,1999:blog-22634878.post-90538853953818848912009-01-28T21:37:00.001+05:302009-02-20T13:30:13.829+05:30

Internet Explorer 6 is having a problem with displaying atom feed documents which's mime type is "application/atom+xml". The browser attempts to download the file instead of rendering it. Simply this happens because browser does not accept or recognize the mime type.A simple hack can be done to avoid this issue from the server side. That is changing the mime type to appication/xml or text/plain,

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com3tag:blogger.com,1999:blog-22634878.post-54971513475871394472008-11-01T12:37:00.010+05:302009-11-05T07:45:40.306+05:30

Replacing a charater in a String is just a matter of adding a one line to the code. originalString.replace(oldChar, newChar) ex. String originalString = "This/is/my/string"; System.out.println(originalString.replace('/', '|')); Then the output will be "This|is|my|string" Anyway how can we replace a character or number of characters(a substring) with another string. This can be done using the

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com9tag:blogger.com,1999:blog-22634878.post-4399925189632798142008-10-30T22:13:00.012+05:302009-02-20T13:29:25.854+05:30

A web server, responding to a HTTP GET request sends the required content to the client. Normally we don't see what is sent between the web client and the server. However we can easily see what is sent by the server by telneting to that web server.To connect to the web server - open a command line and type the commandtelnet host porteg. telnet www.wso2.com 80Then you'll get connected to the

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com9tag:blogger.com,1999:blog-22634878.post-65003878483983485072008-10-06T16:27:00.012+05:302009-02-20T13:28:49.508+05:30

Files having the .ram extension actually don't give any meaning to the word "Play" as they are realplayer meta files only, referring to the actual audio files. To play .ram files you should be connected to the Internet as they are streamed and played.In Ubuntu, you can get a .ram file to play by following the steps below.1. Install Realplayer and the plugin for Mozilla Firefox. (The way to

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com5tag:blogger.com,1999:blog-22634878.post-428721134050474942008-09-30T15:47:00.005+05:302009-02-20T13:28:09.417+05:30

The way of installing fonts is bit different (must say it is pretty simple too) in Ubuntu 8.04.You just have to create a .fonts folder (if it does not exist) in your home folder and copy the TTF to that folder.Well. Thats it :)

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com3tag:blogger.com,1999:blog-22634878.post-53292075893792060172008-09-22T20:33:00.015+05:302009-11-05T08:08:50.499+05:30

The atom publishing protocol (similar to RSS but with an enhanced ability) is an application level protocol for editing and publishing web resources for periodically updated web sites, using HTTP. An atom document which adheres to the Atom syndication format spec, is used as an atom feed or entry. Apache Abdera implements this protocol and exposes a simple API to make the thing easy. The way to

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com5tag:blogger.com,1999:blog-22634878.post-4947279443352694862008-08-26T10:02:00.013+05:302010-02-25T04:11:56.849+05:30

As my previous post shows how to index PDF Documents with Lucene, I thought that it would be worth to post how to index Microsoft format files too because those file types are very commonly used. Lucene always requires a String in order to index the content and therefore we need to extract the text from the document before giving it to Lucene for indexing. To parse the document we can use Apache

kalani Ruwanpathiranahttp://www.blogger.com/profile/16687161472176693636noreply@blogger.com22