Unreachable catch block
Always contruct try-catch blocks in a way that assumes catching Exceptions from more detailed to more generic. Example try { String [] tab = null; System.out.println(tab[3]); } catch (Exception e) { System.out.println(“Exception”); } catch (NullPointerException e) { System.out.println(“NullPointerException”); } The above presented snippet will cause compilation error: Unreachable catch block for NullPointerException. It is already…
adminSun Certified Java Programmer
Okay, I’ve been working with Java for a few years now, starting from academia and ending with business solutions. So yeah, I think I can say I know Java and some of those technologies like J2SE, J2EE or J2ME, with their own standards and solutions. Therefore, I’ve decided I’d take Sun Certified Java Programmer (SCJP)…
Create a report with Reporting Services
If you want to create a report in 5 mins, you should follow this tutorial. All requirement software can be found there. I installed the following: The tutorial instructs you how to create the report (RDL file): how to define the data source, layout and how to preview the report. Once you’re done, you can…
Parser Error Message: This page allows a limit of 200 controls, and that limit has been exceeded.
By default, web.config of SharePoint (should be there: C:InetpubwwwrootwssVirtualDirectories80) defines the maximum number of controls as 200. Should you define more on a page you’ll probably get an error similar to this: Solution In order to fix it, edit this web.config. Find configurationSharePointSafeMode tag and change the MaxControls attribute to a bigger number. Once you…
Is it possible to fail a load test?
It’s not really possible to fail a load test because by default it always ends with status ‘Completed’. Because of that anytime a load test completes one musts analyze the results – if performance stayed at the acceptable level. So, despite being a powerful tool, load tests require human attention, which makes the whole testing…
What if you extend an abstract class and implement an interface when both define a method with the same name?
Imagine you need to implement a class that extends an abstract class and implements an interface when both define a method with the same name – test(). Example interface Implementable { public void test(); } abstract class Superclass { public abstract void test(); } public class Test extends Superclass implements Implementable { /* definition of…
Ireland again
Greetings from Ireland! It’s the second time I went to Galway, Ireland. Again the Green Island welcommed us with rain… Again, I work as a researcher, Java programmer in Digital Enterprise Research Institute (DERI), Galway, Ireland. The main topic of my research is how to adopt Social Semantic Information Sources (SSIS) to e-Learning. Actually, this…
Exeptions and Errors in Java
In the diagram below I present the hierarchy of most common Exceptions and Errors: Object | |_ Throwable | |_ Error | | | |_ AssertionError | | | |_ LinkageError | | | | | |_ ExceptionInInitializerError | | | | | |_ NoClassDefFoundError | | | | |_ VirtualMachineError | | | |_…
Test your Java experience for free – JavaBlackBelt
Recently I’ve come across another very interesting social service – JavaBlackBelt. Basically it gathers programmers who use Java language and related frameworks and aspects (OO programming, JSP, Struts, JSF, EJB). There are even exams on C#, Ruby, JavaScript, and AJAX but some of them are still beta versions. Of course I’ve taken a couple of…
IKHarvester
Some time ago I wrote about Didaskon, a framework for composing curriculum for a specific user, basing on his profile and using formal and informal knowledge. I belong to team of the developers. At the moment, I am developing the one of its component – IKHarvester (Informal Knowledge Harvester). It aims at collecting (harvesting) data…
Didaskon
Here is some information taken from my Master’s Thesis (still developed).. Didaskon is a project developed in Digital Enterprise Research Institute (DERI), Ireland by a few students, including myself. It is a research project in the elearning field. Its main goal is to deliver a framework for assemblying an ondemand curriculum from existing Learning Objects…
Web 2.0 gaming
Recently, I’ve encountered doof, a new Web 2.0 service, kind of “new one”… The authors promote it with the slogan: “Have fun playing games and competing in tournaments, pesonalising your profile and expressing yourself”. Then, what actually doof is? First of all, doof is a fancy website with astonishing flash design (see above). User can…