Java Certification and Skills Assessment

17 August 2005 ⋅ 2 min read ⋅ java

This morning I was surfing around JavaLobby.org to see what’s new. I wasn’t there for a month or so (except those times when I published short announcements for my writings). I was fortunate to notice one interesting link — the link to new JavaLobby network site — JavaBlackBelt. It’s a free skills assessment community which can help you to get prepared to serious certification exams or just give you some fun during the coffee breaks. Below are two books I recommend to pay attention to, if you are going to prepare yourself to exams. Sun Certified … Study Guide (Exam 310-035 & 310-027) by Kathy Sierra, Bert Bates Sun Certified … for Java X Study Guide (Certification Press) by Kathy Sierra, Bert Bates Well, personally, I’m still in two minds about this site. From one side, it is basically a good idea to provide this kind of service — free skills assessment.

Networking specifics under Java Web Start

9 August 2005 ⋅ 4 min read ⋅ java

This writing will help you overcome several annoyances of Java Web Start in respect to networking.

During my development I hit two major problems doing polite networking when running application under Java Web Start: I couldn’t set correct HTTP “User-Agent” string and I couldn’t make application obey connection and reading timeout settings. According to the SUN’s bug reports database these problems are pretty common and that’s why I wished to share my experience with the rest of community, knowing how important to have networking layer working correctly.

Testing Caches

23 February 2005 ⋅ 3 min read ⋅ java

When it comes to testing how you can be sure that the cache releases objects when the VM runs low on memory? This small writing gives some tips about how the running out of memory can be simulated in your test cases safely.

Events Dispatch Thread (EDT) lockup detection

2 February 2005 ⋅ 9 min read ⋅ java

What to do when user interface becomes unresponsive or locks up? How to find out why, when and where? The answer was always near us and as you will see from the article it’s relatively simple. Make a step towards improving the performance of your developments with this revolutionary new watchdog-like performance monitor and detector. No SDK or VM patching. Everything can be done on application level.

Soft property change listeners

1 February 2005 ⋅ 5 min read ⋅ java

In some cases you will wish to have the cache of objects, but what if these objects are registered listeners of some other objects? This hard link between the cached items and persistent ones will not let the first to be garbage collected. The article shows how this misbehavior can be easily avoided using soft-referenced wrapper for your listeners.

Enumeration sub-types

31 December 2004 ⋅ 4 min read ⋅ java

Font for text and font for date are both fonts. Colors for corresponding elements are both colors. Colors and fonts are properties of some theme. You need some constants to read out properties (i.e. fonts or colors) from the theme. The safest and clearest way to have them broken into hierarchy of sub-types. The article is not only about fonts and colors, it’s about general approach to enumeration sub-types and testing of their applications.

Caching asynchronous calculations

23 December 2004 ⋅ 9 min read ⋅ java

Have you ever seen how file managers preparing the thumbnails in background while you are browsing some folder on your drive? If you will switch to the other folder and then get back to first you will see the thumbnails almost instantly. They were calculated asynchronously and cached. Here’s what the text is about.

Simple cross-thread locks

22 December 2004 ⋅ 4 min read ⋅ java

What to do when you wish to lock something in one thread, but unlock it in the other? Smells bad? No. Smells a bit unsafe? Yes. But how on earth it can be done if standard locks can be unlocked only from the threads they were locked at?

JSP and Servlets Feel Bad on Return

1 January 0001 ⋅ 3 min read ⋅ technology java

For the last two weeks I’ve been writing a database editor application with JSP / Servlets. I’m a returning JSP / Servlet programmer with a 7+ year background, but with a 1 year Rails pause. Now that I finished the task, I can share my feelings. Sorry, Java world. It’s not your day.