Category Open Source

NoSQL at Twitter: Why / How they use Scribe, Hadoop/Pig, HBase, Cassandra, and FlockDB for data analytics?


Here’s some interesting NoSQL stuff guys. It’s a presentation about how Twitter uses NoSQL for analytics by Kevin Weil (@kevinweil), Analytics Lead, Twitter. About the presentation Collecting data (Scribe) Storing and Analyzing data (Hadoop) Rapid Learning over Big Data (Pig) .. and Cassandra, HBase, FlockDB. For those who are not aware of the said technologies… […]

Migrating from EJB to Spring and from JBoss to Apache Tomcat: A Real-Life Case Study of Hyperic v4.5 Release


This case study on migrating the open source web application monitoring and management software, Hyperic, to the Spring Framework and Apache Tomcat was originally delivered by Jennifer Hickey at the 2010 SpringOne 2GX conference. This migration work was done for Hyperic v4.5 release. Here are some of the advantages cited about this migration: 1. Improved […]

PooledConnectionFactory vs CachingConnectionFactory: Which one is a perfect match for Spring JmsTemplate?


JmsTemplate, part of Core Spring JMS framework, simplifies the use of JMS since it handles the creation and release of resources when sending or synchronously receiving messages. As discussed in this post – https://singztechmusings.wordpress.com/2011/04/24/problem-with-creating-jms-messageproducer-using-spring-jmstemplate-how-to-solve/ – we need to have pooling in place to make it efficient. We’ve got two JMS provider choices: ActiveMQ‘s PooledConnectionFactory or […]

Capturing web page screenshot using WebDriver API


You can use the below snippet to take screenshot and save it where you want. Commons IO libraries can be downloaded here: http://commons.apache.org/io/download_io.cgi

Using CachingConnectionFactory with Spring JmsTemplate: What problem does it solve?


From Spring framework API docs for org.springframework.jms.core.JmsTemplate, “…The ConnectionFactory used with this template should return pooled Connections (or a single shared Connection) as well as pooled Sessions and MessageProducers. Otherwise, performance of ad-hoc JMS operations is going to suffer. The simplest option is to use the Spring-provided SingleConnectionFactory as a decorator for your target ConnectionFactory, […]

Apache ActiveMQ – How to resolve java.io.IOException: Too many open files exception?


Have worked on ActiveMQ for quite a while, and there’s one annoying exception – java.io.IOException: Too many open files – which we see time to time. [localhost:61613] ERROR TransportConnector – Could not accept connection : Too many open files [or@0.0.0.0:8161] WARN  log – EXCEPTION java.io.IOException: Too many open files at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:145) at […]

Getting started with WebDriver: A simple example


To start with, WebDriver is a tool that’s pretty useful in automating the testing of web apps. As of writing this post, Selenium, another popular and well established testing framework, integrated WebDriver API into Selenium v1 in its Selenium v2.x release. If you’d like to read more about WebDriver and Selenium, click here. What do you […]

Enterprise Messaging with ActiveMQ and Spring JMS


Sharing something that was really helpful to me, when I started working with ActiveMQ.. You can download the pdf here: Download link Here’s the brief list of topics covered, if you’d like to glance over it.. What is ActiveMQ? Configuring/Installing ActiveMQ Wire Formats Transport/Network Connectors Message Persistence Journaled/Non-journaled JDBC Master/Slave Configurations Broker Security Network of […]

How to quickly configure authorization settings in ActiveMQ?


Configuration file: ACTIVEMQ_HOME/conf/activemq.xml Here’s a sample snippet to show you how authentication / authorization can be handled in ActiveMQ. For advanced users – ActiveMQ provides pluggable security through various different providers. Have a look at http://activemq.apache.org/security.html Related articles Spring 3.x – ActiveMQ 5.5 Integration ( JMS Point to Point ) (apachebite.com) ActiveMQ IS Ready For […]