From 755f270a31b5d675c6e8368f87d08f3da1c9ce99 Mon Sep 17 00:00:00 2001
From: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>
Date: Mon, 18 May 2026 19:04:59 +0100
Subject: [PATCH] ci: drop JDK 21 from backend build matrix

JPDFium's published artifacts carry org.gradle.jvm.version=25 (FFM is
finalized at JDK 22+; JPDFium picks 25 as the source target). Gradle's
variant attribute matching refuses to resolve the dep on JDK 21
targets, so the 21 cells in this matrix were guaranteed to fail.

Now that targetCompatibility is bumped to 25 across the project, JDK 25
is the only supported toolchain.
---
 .github/workflows/backend-build.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/backend-build.yml b/.github/workflows/backend-build.yml
index 4fba78c6e2..78d44815d7 100644
--- a/.github/workflows/backend-build.yml
+++ b/.github/workflows/backend-build.yml
@@ -18,7 +18,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        jdk-version: [21, 25]
+        # JDK 25 is the floor: JPDFium's published artifacts require
+        # org.gradle.jvm.version=25 (FFM is final at 22+, JPDFium picked 25
+        # as its source target). Earlier JDKs can't even resolve the dep.
+        jdk-version: [25]
         spring-security: [true, false]
     steps:
       - name: Harden Runner