PlantUML is downloaded by CI at build time

Avoids the need to keep the JAR file within the sources

.circleci/config.yml

@@ -4,6 +4,11 @@ version: 2.0
 default: &default-steps
   steps:
     - checkout
+    - run:
+        # Note: this makes it hard to reproduce builds but easier to spot incompatibilities with
+        # newer PlantUML releases. Current trade off seems acceptable.
+        name: Download the latest PlantUML release
+        command: sh ./bin/download-plantuml.sh
     - run:
         name: Update APT packages
         command: apt-get update

bin/download-plantuml.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+# Where the script is executed
+CURRENT_PATH="$(dirname "$(readlink -f "$0")")"
+
+# Where to download the file
+OUTPUT_PATH="${CURRENT_PATH}/plantuml.jar"
+
+# Retrieve the list of versions, in XML format, only one result (the latest)
+VERSIONS_URL='https://search.maven.org/solrsearch/select?q=g:net.sourceforge.plantuml+AND+a:plantuml&core=gav&start=0&rows=1&wt=xml'
+
+# Only match the contents of the version (name="v") XML tag
+LATEST_VERSION="$(curl "${VERSIONS_URL}" | grep -oP) '(?<=<str name=\"v\">).*?(?=</str>)'"
+
+# Compose the download link
+DOWNLOAD_URL="https://search.maven.org/remotecontent?filepath=net/sourceforge/plantuml/plantuml/${LATEST_VERSION}/plantuml-${LATEST_VERSION}.jar"
+
+# finally, download the JAR file
+curl -o "${OUTPUT_PATH}" "${DOWNLOAD_URL}"