Build with Java 8, 11 or 17

Issue gh-761

buildSrc/src/main/java/org/springframework/gradle/SpringJavaPlugin.java

@@ -80,6 +80,9 @@ public class SpringJavaPlugin implements Plugin<Project> {
 			CompileOptions options = javaCompile.getOptions();
 			options.setEncoding("UTF-8");
 			options.getCompilerArgs().add("-parameters");
+			if (JavaVersion.current().isJava11Compatible()) {
+				options.getRelease().set(8);
+			}
 		});
 		project.getTasks().withType(Jar.class, (jar) -> jar.manifest((manifest) -> {
 			Map<String, String> attributes = new HashMap<>();

gradle.properties

@@ -1,5 +1,5 @@
 version=0.3.1-SNAPSHOT
-org.gradle.jvmargs=-Xmx3g -XX:MaxPermSize=2048m -XX:+HeapDumpOnOutOfMemoryError
+org.gradle.jvmargs=-Xmx3g -XX:+HeapDumpOnOutOfMemoryError
 org.gradle.parallel=true
 org.gradle.caching=true
 springFrameworkVersion=5.3.20