Update build toolchain from Java 17 to Java 21

Author: gredler

.github/workflows/gradle-ci-build.yml

@@ -19,7 +19,7 @@ jobs:
       uses: actions/setup-java@v4
       with:
         distribution: 'temurin'
-        java-version: 17
+        java-version: 21
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v3
       with:

README.md

@@ -155,6 +155,9 @@ and data.
 
 ### Recent Releases
 
+#### Okapi Barcode 0.4.7
+- Update build toolchain from Java 17 to Java 21 (minimum target runtime remains Java 8)
+
 #### Okapi Barcode 0.4.6
 - QR Code: allow FNC1 escape sequences in user-provided content
 - Code 39 Extended: allow empty content, if user requests it

build.gradle

@@ -4,7 +4,7 @@ apply plugin: 'eclipse'
 apply plugin: 'jacoco'
 
 group = 'uk.org.okapibarcode'
-version = '0.4.6'
+version = '0.4.7'
 
 repositories {
     mavenCentral()
@@ -20,8 +20,9 @@ dependencies {
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.10.2'
 }
 
-java.toolchain.languageVersion = JavaLanguageVersion.of(17)
+java.toolchain.languageVersion = JavaLanguageVersion.of(21)
 compileJava.options.release = 8
+compileJava.options.compilerArgs << '-Xlint:-options' // Java 8 target is considered obsolete when building on Java 21; silence this warning
 compileJava.options.encoding = 'UTF-8'
 compileTestJava.options.encoding = 'UTF-8'
 javadoc.options.encoding = 'UTF-8'