Chapter 15. Debugging your Quarkus project

When Quarkus starts in development mode, debugging is enabled by default. The debugger listens on port 5005 without suspending the JVM.

Prerequisites

  • You have a Quarkus Maven project.

Procedure

Use one of the following methods to control debugging:

Controlling the debugger through system properties

  1. Change one of the following values of the debug system property where PORT is the port that the debugger is listening on:

    • false: The JVM starts with debug mode disabled.
    • true: The JVM starts in debug mode and is listening on port 5005.
    • client: The JVM starts in client mode and tries to connect to localhost:5005.
    • PORT: The JVM starts in debug mode and is listening on PORT.

  2. Change the value of the suspend system property. This property is used when Quarkus starts in debug mode.

    • y or true: The debug mode JVM launch suspends.
    • n or false: The debug mode JVM starts without suspending.

Controlling the debugger from the command line

  • To start your Quarkus application in debug mode with JVM, enter the following command: 

    ./mvnw compile quarkus:dev -Ddebug

Enabling the debugger for a specific host domain

In development mode, the debugger is only enabled for applications that you execute on localhost. You must manually enable debugging on other hosts.

  • Use the debugHost option to enable debugging on a specific host. You must replace <host-ip-address> with the IP adress of the host for which you want to enable debugging. 

    ./mvnw compile quarkus:dev -DdebugHost=<host-ip-address>

    To enable debugging on all hosts, replace <host-ip-address> with 0.0.0.: 

    ./mvnw compile quarkus:dev -DdebugHost=0.0.0.0