Use 'release' setting instead of 'compatibility' setting for compileJ…

…ettyTestJava because of certain methods not found in `Deprecated` class with source compatibility specified at 1.8 https://github.com/grpc/grpc-java/actions/runs/13155287866/job/36710941635

gradle/libs.versions.toml

@@ -53,10 +53,8 @@ guava-jre = "com.google.guava:guava:33.3.1-jre"
 hdrhistogram = "org.hdrhistogram:HdrHistogram:2.2.2"
 # 6.0.0+ use java.lang.Deprecated forRemoval and since from Java 9
 jakarta-servlet-api = "jakarta.servlet:jakarta.servlet-api:5.0.0"
-# Not using the relocated org.apache.tomcat:tomcat-annotations-api because it requires migrating
-# java.annotation to jakarta.annotation. According to
-# https://github.com/grpc/grpc-java/issues/6833#issuecomment-602242609
-# there are so many different artifacts containing it, which causes classpath collisions.
+# Using javax.annotation is fine as it is part of the JDK, we don't want to depend on J2EE
+# where it is relocated to as org.apache.tomcat:tomcat-annotations-api. See issue #7179.
 javax-annotation = "org.apache.tomcat:annotations-api:6.0.53"
 javax-servlet-api = "javax.servlet:javax.servlet-api:4.0.1"
 # 12.0.0+ require Java 17+

servlet/jakarta/build.gradle

@@ -37,11 +37,6 @@ configurations {
     undertowTestImplementation.extendsFrom(itImplementation)
 }
 
-java {
-    sourceCompatibility = JavaVersion.VERSION_1_8
-    targetCompatibility = JavaVersion.VERSION_1_8
-}
-
 // Mechanically transform sources from grpc-servlet to use the corrected packages
 def migrate(String name, String inputDir, SourceSet sourceSet) {
     def outputDir = layout.buildDirectory.dir('generated/sources/jakarta-' + name)
@@ -115,6 +110,9 @@ if (JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_17)) {
         classpath = sourceSets.jettyTest.runtimeClasspath
         testClassesDirs = sourceSets.jettyTest.output.classesDirs
     }
+    tasks.named('compileJettyTestJava') { JavaCompile task ->
+        task.options.release.set 8
+    }
     tasks.named("check").configure {
         dependsOn jetty11Test
     }