You have several options to get jRegExAnalyser up and running on your machine. jRegExAnalyser is licensed under the conditions of the GPLv2 with Classpath Exception.
First, make sure you have an up-to-date version (>= 1.6.0 / Java 6 SE) of the Java Runtime Environment or Java Development Kit installed.
Then choose one of the following options:
You can start jRegExAnalyser without installation using Java Web Start: http://jregexanalyser.schwebke.com/jregexanalyser.JNLP
An application running in the Web Start environment sandbox has only restricted access to the machine. Depending on your security settings, you might have to confirm security dialogues for some operations, for example text file import. Also some comfort functions, like cut'n'paste in the text fields or remembering the directory of the last text import, will not work due to these restrictions.
Download the jRegExAnalyser binary distribution from http://jregexanalyser.schwebke.com/, extract the archive and start jRegExAnalyser.jar. Depending on your desktop environment this may be a simple click or double click. Or you can explicitly start the .jar file with the Java runtime:
java -client -jar jRegExAnalyser.jar.
For Unix desktop environments (LXDE, KDE, Gnome, ...) you may edit jregexanalyser-install (if changes are required) and run the script as root to install an application menu entry.
For Windows you may link the jregexanalyser.exe to your desktop or start menu.
Your user preferences will be stored in the file .jregexanalyser in your home directory.
Currently Netbeans 7.2 is used for development. (1)