arundhaj

all that is technology

Connecting internet with USB modem - Raspberry Pi

 

After some exploration, I could successfully connet to the internet with Tata Photon Plus from my Pi. Though with Raspbian, it is not as straight forward as it is with any other Linux varient.

There are many options available for connecting to the internet, based on the available infrastructure. In …

J2EE server for Webfaction

 

Webfaction doesn't have j2ee web servers by default. Users have to install it manually, by creating a "custom application listening on port".

I first started with Apache Tomcat, later ended with high memory usage than permitted for my account. My account's limit is 256MB RAM, however Tomcat was consuming around …

UnsupportedClassVersionError unsupported major.minor version 51.0

 

For J2EE webapps, when development environment is different from production environment, deploying could be tedious.

One such issue I encountered is the difference in JDK version. My development machine have latest JDK1.7 whereas my production servers have JDK1.6. When deploying the war on this server, I was getting …

Hbase row filter with regex

 

Querying Hbase rows based on RegEx with spring-data-hadoop framework; following code snippet would help.

To keep it simple, I query the table to get only those row keys that match my INPUT. In this case the row key structure is 10 digit followed by a string.

String name = String.format …

Spring data hadoop webapp

 

When I got started to try spring-data-hadoop as a webapp, I found no samples online. All tutorials were either with configurations or as a standalone application. With a bit of experiments and exploration I managed to create a simple webapp and hosted it on my local tomcat server. I've uploaded …

HibernateException No Session found for current thread

 

While programming a web application with Spring and Hibernate, came across HibernateException: No session found for current thread. Apparently found out I was missing @Transaction which was causing trouble.

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.HibernateException: No Session found for current thread
    org …

Disable animation and improve Ubuntu performance

 

Today I've installed Ubuntu 12.10 (Quantal Quetzal). The system is solid; over few minutes of hands-on, one part that bothered me was the windows animation. As a software developer, I know, how difficult it is to implement animation. However, my machine is not fast enough to catch up with …

Moving folders between SVN repos

 

To move a folder or document between SVN repositories by retaining history, following steps would help.

Step I

Dump the entire svn repository to a dump file with svnadmin dump. If the repository is too big to dump, better pipe the next two commands. Command here is split in the …

getGeneratedKeys with PostgreSQL

 

In a complex SQL transaction where the tables are normalized and split, it becomes necessary to put primary key of first tables' insert as a foreign key of subsequent tables' inserts. Though java.sql.PreparedStatement have getGeneratedKeys, it works pretty different for PostgreSQL than MySQL.

The following code block shows …