2011-09-27
I have just finished writing a program that is able to import mails stored in a MH mailbox to an IMAP server. During the development I had to get over some obstacles which I want to share here. But first thing first: The user story for the program.
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Migration from Weblogic 10g to 11g and Java Webstart
2011-08-30
The last days I was migrating an application from Weblogic 10g to 11g. The application had a Swing client as frontend. The Swing client used stubs that were created during building the server. For the build I've used tools/libs of a local Weblogic installation. To test the migrated server I've started the client from my IDE. I've got up to the point where this local client worked perfectly with the migrated server backend. Then I've deployed the frontend to the webstart repository and started it. The application didn't start but I've got this exception:
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Format Oracle sqlplus ouptput
2011-08-23
A co-worker needed to get some data from our production database. So he sent a sql query to the database administrators. As the result he got the output of sqlplus. Neither he nor the database administrator had specified a custom format for the output. As the query had a couple of columns as output the result was that the rows were broken into two lines. My co-worker asked me to prepare the output so that it could be analyzed in Excel.
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C programming by a Java developer
2011-08-21
At the beginning of the millennium I've learned C and did some small hobby projects but then focused on Java. I've tried once in a while to do some C but coding C in a text editor compared to program Java with Eclipse is a total mess. In fact IDEs like Eclipse are the reason why I stick with Java and didn't go to the new shiny JVM languages like Groovy. At the end of the day I'm faster with Java and Eclipse than with Groovy and a text editor. Then there was the release of Eclipse 3.7 and I've thought that I may give C a chance again.
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Assembling and installing new computer
2011-08-20
I've got a new computer. It has a quad core CPU, 8GB RAM, is relatively quiet, and didn't cost a fortune. Sounds too good to be true? Well, it has no dedicated graphic card and I didn't by it off the shelf but instead assembled it on my own.
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The power of Eclipse autocompletion
2011-08-18
Today I've accidentally found a pretty cool feature of Eclipse autocompletion: It will recognize instanceof checks and offer the method of the checked class.
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Clone virtual box guest OS with cp
2011-08-17
When you clone a virtual box guest OS via cp command you have to execute this steps:
- cp the VDI file that is the HDD of the OS you want to clone.
- execute: VBoxManage internalcommands sethduuid <copied VDI file>
- Check if you network card switched from eth0 to eth1. This is very likely as the mac address is stored in the file /etc/udev/rules.d/70-persistent-net.rules. A new mac address gives you a new ethX interface. Delete the entry for eth0 and rename eth1 to eth0 if you want eth0 back.
- You may want to change /etc/hostname and /etc/hosts when the cloned system should get a new name.
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The LMAX Architecture
2011-08-14
Recently I've stumbled over an a question on how to significantly improve java performance on stackoverflow.com. The question was inspired by an article of Martin Fowler about the The LMAX Architecture where he describes the architecture of a trading software made by the company LMAX. The have made a Business Logic Processor that can handle 6 million orders per second. Whats so great about it? Well, it is single threaded. Yes, there is only one thread that executes the whole business logic.
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Fun with Java Web Start
2011-08-13
This week I wanted to get information out of a program started via Web Start. Why Web Start? Because I've found no other way to get JAWS recognizing my application. First I wanted to do remote debug of the application. I've placed the remote debug switch
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Get CPU information under Linux
2011-08-11
Need some information about you CPU under Linux? To get the scaling governor (tells how your CPU should set their frequency, e.g. low as possible when there is no work, or maximum all the time) and the current scaling (current frequency) use the following two lines:
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