Remote Debugging#

Janssen Server modules run as Java processes. Hence, like any other Java process the JVM running the module can be configured to open a debug port where a remote debugger can be attached. The steps below will show how to configure auth-server module for remote debugging.

Pass the command-line options to the JVM

On the Janssen Server host, open the service config file /etc/default/jans-auth and add the following JVM parameters to as JAVA_OPTIONS

-Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=6001

This will open the port 6001 for the remote debugger. Any other port can also be used based on availability.

Restart jans-auth services
```
systemctl restart jans-auth.service
```
Check if the port is open and accessible from within the Janssen Server host Use the jdb tool from JDK to test if the JVM port has been opened
```
./<path-to-JDK>/bin/jdb -attach 6001
```
if the port is open, it'll give you output like the below:
```
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
Initializing jdb ...
>
```
press ctrl+c to come out of it.
Ensure that the port is accessible from outside the host VM as well and firewalls are configured accordingly
Connect to the remote port on the Janssen Server host from the developer workstation. Use any IDE (Intellij, Eclipse, etc.) to create and run a remote debugging profile. Provide IP and debug port of the Janssen Server host.

For IntelliJIdea, create a debug configuration as below:

Last update: 2025-05-15
Created: 2025-05-15