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Showing posts from August, 2013

JVM Garbage Collection and Optimizations

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Overview When troubleshooting systems for performance-related issues, memory optimizations are a place that needs a deep analysis of what each system stores in the memory, how long those are stored, and access patterns. This post is to keep a note on the background information and valuable points to note in such an effort, specific to Java-based implementations as a deep understanding of the JVM behaviors is very beneficial in the process.

Java language provides much convenience to the developers by taking care of the memory management to a great extent letting the focus be on the rest of the logic. Still having a good understanding of how Java does this underneath, rationalize several best practices we follow in Java implementations and help design the programs better and think seriously on some aspects that can later lead to memory leaks and system stability in the long run. Java Garbage Collector has a big role in this been responsible for freeing up memory by removing memory gar…

WSO2 Identity Server 4.5.0 brings support for dynamic configuration of multiple user stores

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WSO2 Identity Server 4.5.0 is going to be released by the end of this month, with a new set of features and lot of improvements to the existed features. Allowing dynamic configuration of multiple user stores is one such new addition in this release, that improves the flexibility of the server to cater changes in the production environments.

This feature comes in handy when a requirement occurs to add more user stores, change some attributes of an existing user store or remove a user stores from the existing ones. With this new user store configuration UI, above scenarios can be executed smoothly and burden of editing XML files is taken away. This operates in dynamic manner that no server restart is required and changes are effective in few seconds.

Here are few screen-shots of the UI to be released.
The default view of user store configuration UI(Configure>User Store Management) will be as follows, when there are no secondary user stores added. (we will refer all the user stores a…

How to Install Windows in a Virtual Machine in Linux(Ubuntu)

Recently I wanted to run Windows inside my Primary OS -  Ubuntu 12.04. I didn't want to go for dual boot option so I decided to use a virtual machine and install Windows inside Ubuntu. I faced couple of problems and here share my experience with how I overcame them.
In choosing a Virtual machine I tried out 2 options. Oracle VM VirtualBox and VMware Player that is available in Ubuntu Software Centre. I could create a virtual machine successfully hitting 'new' button and following the wizard. Then I started the created machine, pointing to the CD image. It tried to load Windows files and then printed the following error on screen.
Attempting to load a 64-bit application, This CPU is not compatible with 64-bit mode. But my machine has a 64 bit processor. So something has gone wrong. The issue has been my BIOS settings in the host machine has not enabled hardware virtualization. So I manually did it. My machine was a Lenovo ThinkPad T530 and could find this setting under sec…