Another useful tool from Zeroturnaround – Xrebel

Some time ago I signed up for a beta testing of a new tool from Zeroturnaround : Xrebel. I have been waiting a bit impatiently for a testing program to start. Finally I have got an information about availability of 1.0.0 version of the tool for download. Without much hesitation I have started tests.

What does the tool do?

As you may expect, based on previous Zeroturnarond tools, generally speaking it is intended to improve quality of Java developer every day work. More precisely speaking it allows developers to live monitor JVM application in regards of session size and SQL queries sent to the underlying database.


There is no doubt that Zeroturnaround guys know all the ins and outs of JVM so the installation is as simple as adding -javaagen:[path]xrebel.jar JVM parameter to the application server. And that is it. Starting an application server the following output is presented:


Application successfully started with Xrebel assist.

When web application is executed in the web browser for the first time with Xrebel there is a simple form presented in the web browser allowing user to activate the tool.

Let’s discover tools features.


When the application is executed in the web browser Xrebel adds small toolbar on the left side of the screen:

Picture 1. Toolbar
Picture 1. Toolbar

When first click on any option the Setting window is showed when user can enter package name which will be monitored and thresholds which will be used by Xrebel to notify user when exceeded:

Picture 2. Package settings
Picture 2. Package settings


Picture 3. Thresholds settings
Picture 3. Thresholds settings


I expected easy set up and Xrebel did not disappointed me.


Main feature of the Xrebel is live application monitoring and as shown on Picture 1. general information are presented on the toolbar itself. First sections regards SQL queries. First number (5) indicates number of SQL queries executed so far. Next position shows queries execution time (288.5 ms). Section below shows session information: total size and size difference from the last request.

When clicked on each session additional information is presented such as exact query executed in the database, number of rows returned and execution time:


As far as session is concerned, there are sizes of each stored element.


The main purpose of the Xrebel is to quickly find bugs regarding dodgy database access and abnormal session size increment. In my opinion, even it is early beta version, it fulfills expectations.
Simple, not disturbing tool providing all information needed for a developer to track down the issue cause.

If you feel interested in the tool sign up for Xrebel beta testing:

Xrebel beta tests