Design pattern to scale relational database horizontally

December 11, 2017 Leave a comment

Database scalability is one of the critical factor in designing scalable web application. All the four major cloud vendors (Amazon, Microsoft, Google and Oracle) offers relational database as service which abstracts several complexities for developers to setup and manage database servers that helps developers focus on core application development. Even with cloud vendors’ service based offering scaling database horizontally (or scale out) still a challenge which developers can resolve at application level. In this post I would like to talk about the challenges and possible solution for same.

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Filed under Java

Monitoring HttpSession memory leak during JavaEE development

October 2, 2014 Leave a comment

In my previous post I have provided a sample servlet filter to monitor non-serializable objects in HttpSession to make the JavaEE application compatible for clustered environment. We have enhanced the same servlet filter to log HttpSession object size which is helping us to find the memory leak during the development.

Here is the Java code
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Filed under Java

Java: Sample Active Directory authentication code

January 3, 2014 17 Comments

Here is a sample Java code to authenticate against Windows Active Directory server.

  • The code finds all available active directory servers in your network.
  • It uses one of the available active directory server for authentication.
  • If an active directory server is down then it starts using next available server if any.
  • This class is thread-safe, you can create one instance and re-use them multiple times.
  • I tested this code from Linux and Windows box.

You can find the below source code in GitHub as well.
ActiveDirectoryAuthentication.java
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Filed under Java, Java EE, Open Source

Some statistics on programming language

October 15, 2013 Leave a comment

Some interesting statistics on open source programming language based on TIOBE Programming Community Index.

Programming Language First
Released		 Ratings
Oct 2013
C

1972

17.25%
Java

1995

16.11%
C++

1980

8.66%
PHP

1995

6.09%
Python

1991

3.11%
JavaScript

1995

2.04%
Perl

1987

1.61%
Ruby

1993

1.25%
Groovy

2003

0.66%
Scala

2003

0.35%
Haskell

1990

0.25%

Source:

http://www.tiobe.com/tpci.htm

http://en.wikipedia.org/wiki/History_of_programming_languages

Filed under Open Source, Software Engineering, Web

JavaEE – Clustering support in JSF, Wicket, ZK, etc.

October 13, 2013 2 Comments

When a seasoned MVC framework developer starts writing code in component based framework like JSF, Wicket, ZK, etc. they fail to understand the basic differences between MVC and component based framework because they could write code which can work in non-clustered environment i.e. in single JVM deployment. When the same application is deployed in a clustered environment they start realizing the difference which will require lots of effort revisit all the code and make it compatible for clustering. I am going to talk about a few guidelines on making development (on top of component based framework ) cluster aware.
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Filed under Java, Java EE, Web

Simple vs. Complex design

October 7, 2013 Leave a comment

Some of my favorite quotes and comments about simple vs. complex design.

  • achieving a simple, elegant design is very hard work but
  • since the design is so simple and elegant it looks like it should be easy.
  • so you get less credit than if you design something that looks complicated

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Filed under Critic

Capture Heap dump from Tomcat Windows Service

October 4, 2013 Leave a comment

Add the following options into Tomcat >> Java >> Java Options

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=8086
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false

  • Goto JAVA_HOME/bin directory and launch jconsole.exe application
  • In the remote process box enter localhost:8086 and click Connect button
  • Switch to the MBeans tab
  • select com.sun.management – HotSpotDiagnostic – Operations – dumpHeap in the tree on the left
  • Pressing the dumpHeap button creates the heap dump. The parameter called p0 allows you to specify into which target file the heap is dumped.

Filed under Java

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