# Debug Protégé

This page describes how to debug the Protégé Plugin of Ontop from IntelliJ.

If you just want to test the plugin (without debugging), you only need to follow the step of building the Protégé plugin, and then run Protégé as usual (use run.bat on Windows)

$ Protege-[protege-version]/run.sh

# Build the Protégé plugin

# Requirements

Checkout and build Ontop source code as described here. We assume all commands listed below are issued from the root directory of Ontop source tree.

# First time build

Unzip the Ontop Protégé bundle (obtained by previously building Ontop source code), which contains Protégé preconfigured with the Ontop Protégé plugin

$ unzip protege/distribution/target/ontop-protege-bundle-platform-independent-[ontop-version].zip


  • for older versions of Ontop (before 5.0.0) the bundle to unzip is located either in build/distribution/ontop-protege (up to 4.0.3) or in build/distribution/target (up to 5.0.0 excluded);
  • you may also reuse a (platform independent) Protégé distribution obtained directly from Protégé web site and already installed locally. In this case make sure that the Protégé version matches the one used during Ontop build, that Protégé directory contains a plugins sub-directory (create it if missing), and run the commands below to deploy the Ontop Protégé plugin (adapting paths accordingly).

# Subsequent builds

Each time you modify the code, you need to recompile and build the Ontop distribution.

The fastest command to re-compile the Ontop Protégé plugin and the code it depends on is

$ mvn clean package -Dmaven.test.skip -Passet-plugin -pl protege/distribution -am


  • clean package forces a full re-build and may be generally omitted (which defaults to running package) unless you encounter build errors, in which case clean helps ruling out they stem from incremental builds;
  • -Dmaven.test.skip disables compiling and executing unit tests;
  • -Passet-plugin activates the generation of the Ontop Protégé plugin (OSGI bundle with all its dependencies), without including other uneeded artifacts (e.g., full ZIP/tar.gz Protégé bundles, source and Javadoc JARs, etc);
  • -pl protege/distribution -am (optional) tells Maven to only build the Ontop Protégé module located in protege/distribution and all the other Ontop modules it depends on, saving another couple of seconds.


  • in Ontop versions 4.1 to 5.0.0 excluded, the command above should be replaced by mvn clean package -Dmaven.test.skip -Pprotege -pl client/protege -am;
  • in Ontop version 4.0.3 or earlier, the command above should be replaced by mvn clean install -pl client/protege -am -DskipTests to compile code and install it in local maven repository, followed by mvn bundle:bundle -pl client/protege to package the plugin.

Once the Ontop Protégé plugin is built, it must be copied to the Protégé plugin directory via

$ cp protege/distribution/target/it.unibz.inf.ontop.protege-[ontop-version].jar Protege-[protege-version]/plugins/

The command above should replace any previous Ontop Protégé plugin in the plugins directory. In any case, make sure that there is only one Protégé plugin in Protege-[protege-version]/plugins/

# Debug in IntelliJ using the Remote debugger

# IntelliJ configuration

Create a remote configuration:

  • select 'Edit configurations', click '+', then select 'Remote'
  • Host: localhost
  • Port: choose a port number (5005 in what follows)

# Protégé run options

Edit the script Protege-[protege-version]/run.sh (on Windows: run.bat), adding the following JVM option (note that parameter suspend is set to y)


# Run / Debug

Execute Protege-[protege-version]/run.sh (on Windows: run.bat). Then, from IntelliJ, click on the Debug button (or Shift+F9).