Try to use a virtual display

Author: jsotuyod

.ci/build.sh

@@ -20,7 +20,8 @@ function build() {
 
     if pmd_ci_utils_is_fork_or_pull_request; then
         pmd_ci_log_group_start "Build with mvnw"
-            ./mvnw clean verify --activate-profiles shading --show-version --errors --batch-mode --no-transfer-progress
+            Xvfb :99
+            DISPLAY=:99 ./mvnw clean verify --activate-profiles shading --show-version --errors --batch-mode --no-transfer-progress
         pmd_ci_log_group_end
         exit 0
     fi