Most interesting links of September

The most interesting articles and other IT resources I’ve encountered the previous month, delayed a bit due to my holiday in Andalusia. In no particular order. Included some performance stuff, few tools and few general SW engineering things. The Open-Closed Principle , i.e. open to extension, closed to modification – one of the basic principlesContinue reading “Most interesting links of September”

The power of batching or speeding JDBC by 100

We all know that one coarse-grained operation is more efficient than a number of fine-grained ones when communicating over the network boundary but until recently I haven’t realized how big that difference may be. While performing a simple query individually for each input record proceeded with the speed of 11k records per hour, when IContinue reading “The power of batching or speeding JDBC by 100”

Exposing a POJO as a JMX MBean easily with Spring

JMX is a great way to check or change state variables or invoke a method in a (remote) running application via a management GUI such as JConsole. And Spring makes it trivial to expose any POJO as a JMX MBean with only little configuration in a few minutes. The Spring JMX documentation is very good,Continue reading “Exposing a POJO as a JMX MBean easily with Spring”

Implementing retrial with a MDB or an MQ batch job? (WAS 7, MQ 6)

We need to listen for messages distributed via Websphere MQ to get informed when an employee joins or leaves IBM. And because the resources used in the processing (a database, a webservice) may be temporarily unavailable, we must be able to deal with such outages, which may range from minutes to hours, by repeatedly retryingContinue reading “Implementing retrial with a MDB or an MQ batch job? (WAS 7, MQ 6)”

Jetty-maven-plugin: Running a webapp with a DataSource and security

This post describes how to configure the jetty-maven-plugin and the Jetty servlet container to run a web application that uses a data source and requires users to log in, which are the basic requirements of most web applications. I use Jetty in development because it’s fast and easy to work with.

SSH magic: Authorize only once for multiple ssh/scp invocations

OpenSSH has a nice feature that makes it possible to open one “master connection”, which can be shared by multiple subsequent ssh/scp/sftp “slave connections”. The advantage is that you need to supply password only when opening the master connection and thus you can easily perform a sequence of remote commands without constant re-authentication. Let’s seeContinue reading “SSH magic: Authorize only once for multiple ssh/scp invocations”