Make sure that we compile to JRE 11.

jvm/CHANGELOG.md

@@ -11,6 +11,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Restore support for JRE 11. (fixes [#528](https://github.com/diffplug/selfie/issues/528))
 
 ## [2.5.2] - 2025-04-28
 ### Fixed

jvm/gradle.properties

@@ -10,4 +10,6 @@ ver_OKIO=3.9.0
 ver_KOTLIN_TEST=2.0.0
 ver_KOTLIN_SERIALIZATION=1.7.3
 # Kotest 5.4.0 is the oldest that we support
-ver_KOTEST=5.4.0
+ver_KOTEST=5.4.0
+
+ver_JVM_TARGET=11

jvm/gradle/jvm-target.gradle

@@ -0,0 +1,29 @@
+if (plugins.hasPlugin('org.jetbrains.kotlin.jvm')) {
+    kotlin {
+        compileKotlin {
+            kotlinOptions {
+                jvmTarget = "$ver_JVM_TARGET"
+            }
+        }
+    }
+    tasks.named('compileJava', JavaCompile) {
+        options.release = Integer.parseInt(ver_JVM_TARGET)
+    }
+} else if (plugins.hasPlugin('org.jetbrains.kotlin.multiplatform')) {
+    kotlin {
+        jvm {
+            compilations.all {
+                kotlinOptions {
+                    jvmTarget = "$ver_JVM_TARGET"
+                }
+            }
+        }
+        targets.withType(org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget) {
+            compilations.all {
+                kotlinOptions {
+                    jvmTarget = "$ver_JVM_TARGET"
+                }
+            }
+        }
+    }
+}

jvm/selfie-lib/build.gradle

@@ -58,4 +58,5 @@ tasks.create('test') {
 
 // it all needs to get published and formatted
 apply from: 干.file('base/maven.gradle')
-apply from: 干.file('base/sonatype.gradle')
+apply from: 干.file('base/sonatype.gradle')
+apply from: rootProject.file('gradle/jvm-target.gradle')

jvm/selfie-runner-junit5/build.gradle

@@ -35,3 +35,4 @@ test {
 // it all needs to get published and formatted
 apply from: 干.file('base/maven.gradle')
 apply from: 干.file('base/sonatype.gradle')
+apply from: rootProject.file('gradle/jvm-target.gradle')

jvm/selfie-runner-kotest/build.gradle

@@ -59,3 +59,4 @@ jvmTest {
 // it all needs to get published and formatted
 apply from: 干.file('base/maven.gradle')
 apply from: 干.file('base/sonatype.gradle')
+apply from: rootProject.file('gradle/jvm-target.gradle')