In many (most?) systems performance is an important non-functional requirement. And even if you attained the required performance, it is useful to keep an eye on it to detect if a codechange involuntarily deteriorates it. Enter the Performance plugin for Jenkins. Using it you can record the performance (as in ...

Usually it is as simple as: download, install, run. You can run into problems however if you have both the 32 bit and 64 bit JVMs installed (which is quite often) because it will try to use the 32 bit JVM. You can check which JVM is being used from ...

As I found out “on my own skin”, setting fs.file-max in /etc/sysctl.conf is a BAD idea. It can render your system useless in one step. Please don’t do it! If you did it, use the recovery mode to roll back the change. Also, currently I would ...

I have the following problem: a Java application was running out of memory. It was not feasible to mandate 64 bit JVM for this application and the \~1.4G limit wasn’t enough.

My solution was to implement a Map which - when an element is added - also saves the value ...

Crossposted from the Transylvania JUG website.

Microbenchmarking is the practice of measuring the performance characteristics (like CPU, memory or I/O) of a small piece of code to determine which would be better suited for a particular scenario. If I could offer but one advice on this, it would be ...

Some time ago I came over the following article: Fast CRC32 in Assembly. It claimed that the assembly implementation was faster than the one implemented in C. Performance was always something I’m interested in, so I repeated and extended the experiment.

Here are the numbers I got. This is ...

If you have multiple versions of your code in production, it is extremely useful for the log to include the version of the classes when producing a stacktrace, otherwise it is very hard to match the lines in the stacktrace with the lines of the source code (sidenote: there is ...

Sometimes you have the situation that an issue is only occurring on certain machines or only at a certain time of day. There are a couple of possible methods to investigate such an issue (like: adding extra logging), however I would like to add an other one: remote debugging trough ...

Update: this article has been crossposted to the Transylvania JUG blog.

The Java collections framework includes the concept of NavigableSets / NavigableMaps. The principle behind these interfaces is that taking a SortedSet/SortedMap you can use a subset of it. Some examples:

Given the following set:

@Before
public void ...