build(deps): bump Android Gradle Plugin to 9.3.0 on JDK 21 only

.github/workflows/build.yml

@@ -26,7 +26,17 @@ jobs:
         # made JDK-specific by their compile targets:
         #   logback-android      -> Java 11 bytecode, minSdk 26
         #   logback-android-jdk8 -> Java 8 bytecode, minSdk 21
-        java: [17, 21]
+        #
+        # agp: the Android Gradle Plugin version to build with (overrides the
+        # gradle.properties default). AGP 9.3.0+ lint requires JDK 21, so JDK 17
+        # stays on 9.2.1 while JDK 21 exercises the newer plugin.
+        include:
+          - java: 17
+            agp: '9.2.1'
+          - java: 21
+            agp: '9.3.0'
+    env:
+      ORG_GRADLE_PROJECT_agpVersion: ${{ matrix.agp }}
     steps:
       - name: Checkout
         uses: actions/checkout@v7

build.gradle

@@ -6,7 +6,7 @@ buildscript {
     mavenCentral()
   }
   dependencies {
-    classpath 'com.android.tools.build:gradle:9.2.1'
+    classpath "com.android.tools.build:gradle:${agpVersion}"
 
     // NOTE: Do not place your application dependencies here; they belong
     // in the individual module build.gradle files

gradle.properties

@@ -13,6 +13,12 @@ VERSION_CODE=3020000
 
 slf4jVersion=2.0.7
 
+# Android Gradle Plugin version. Defaults to 9.2.1, which still builds under
+# JDK 17. CI overrides this to a newer AGP only on the JDK 21 matrix leg (see
+# ORG_GRADLE_PROJECT_agpVersion in .github/workflows/build.yml): AGP 9.3.0+
+# lint requires JDK 21 (it calls java.util.List.removeLast(), a JDK 21 API).
+agpVersion=9.2.1
+
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
 # Ensure important default jvmargs aren't overwritten. See https://github.com/gradle/gradle/issues/19750