use jdk21

tasks/compile.yml

@@ -13,8 +13,8 @@
 
 - name: Ensure JDK is installed
   fail:
-    msg: "You must have JDK 17 or later installed. {{ 'No version found.' if jdk_version is failed else 'Found version ' + jdk_version.stdout }}"
-  when: jdk_version.stdout is version('17.0.0', '<')
+    msg: "You must have JDK 21 or later installed. {{ 'No version found.' if jdk_version is failed else 'Found version ' + jdk_version.stdout }}"
+  when: jdk_version.stdout is version('21.0.0', '<')
 
 - name: Clone Besu Sources
   git:
@@ -25,7 +25,7 @@
     depth: 1
 
 - name: Build Besu
-  shell: "JAVA_HOME=$(update-java-alternatives --list | grep 17 | tail -n 1 | awk '{print $3}') ./gradlew --no-daemon --parallel clean assemble"
+  command: ./gradlew --no-daemon --parallel clean assemble
   args:
     chdir: /tmp/besu
   changed_when: true