As development team we decided to write our documentation with Asciidoc. As other parts in our landscape use gradle as the build tool, thus we opted for the asciidoctor-gradle-plugin to generate the documentation. The documents have embedded plantuml diagrams describing the architecture, but to our surprise the toolchain did not render them correctly. Apparently the diagrams use features of plantuml that are not supported in the version provided by default by the toolchain.

We found out we had to update to later versions of asciidoctorj-diagram and plantuml. The version of asciidoctor-gradle-plugin (3.3.2) is now about a year old (from February 2021) and probably its dependencies also. Unfortunately it’s rather hard to find which versions are used by the asciidoctor-gradle plugin and how to update to newer versions.

Finding the default versions

Going over the Asciidoctor Gradle Plugin documentation you can read how to set the version of modules you intend to use. But the documentation contains "only" a placeholder version, and not the actual (default) version. Continuing the search leads to the asciidoctor-gradle-plugin source code on github. It contains a file that contains the version of modules used by the plugin suite. Given this file you see the used version of asciidoctorj-diagram is 2.0.5, and not the latest 2.2.1 as of writing.

Listing 1. build.gradle snippet
plugins {
  id 'org.asciidoctor.jvm.pdf' version '3.3.2'
  id 'org.asciidoctor.jvm.gems' version '3.3.2'

asciidoctorj {
  version '2.5.3' 1
  modules {
    diagram.version '2.2.1' 2
  1. The version of asciidoctorj is also not the latest (2.4.1). Updated to 2.5.3.
  2. Update the version of asciidoctorj-diagram to 2.2.1 as that is the latest.

Plantuml used needs an update

With this you expected the beautiful plantuml diagrams you created, but alas still no success.

Version 2.2.1 of asciidoctorj-diagram a version of plantuml which also isn’t the latest greatest. Digging further you can discover that asciidoctorj-diagram wraps the ruby gems asciidoctor-diagram and asciidoctor-diagram-plantuml, the latter wrapping plantuml. The used version of asciidoctor-diagram-plantuml is declared in a file and is version 1.2021.8. Using the Ruby GEM support of the asciidoctor-gradle you can declare a dependency on the latest asciidoctor-diagram-plantuml gem 1.2022.1.

Listing 2. build.gradle snippet
repositories {

dependencies {
  asciidoctorGems 'rubygems:asciidoctor-diagram-plantuml:1.2022.1'  1
  1. Declare the dependency on the asciidoctor-diagram-plantuml gem.

Now you’re using the latest version of asciidoctorj-diagram and the latest version of plantuml. The result is the beautiful diagrams as expected.

Written using gradle 7.3, asciidoctor-gradle 3.2.2,