try to set outputDir but does not work yet

build.gradle

@@ -3,7 +3,7 @@ import org.gradle.internal.os.OperatingSystem
 import org.jabref.build.JournalAbbreviationConverter
 import org.jabref.build.xjc.XjcPlugin
 import org.jabref.build.xjc.XjcTask
-
+import com.apollographql.apollo.gradle.internal.DefaultCompilationUnit
 // to update the gradle wrapper, execute
 // ./gradlew wrapper --gradle-version=6.0 --distribution-type=bin
 
@@ -217,8 +217,6 @@ dependencies {
     // GraphQL integration
     implementation ("com.apollographql.apollo:apollo-runtime:2.5.8"){
         exclude module: "apollo-api"
-        exclude module: "apollo-api-jvm"
-
         exclude module: "apollo-normalized-cache"
     }
 
@@ -411,6 +409,11 @@ apollo {
   useJavaBeansSemanticNaming.set(true)
   rootPackageName.set("org.jabref.jabrefonline")
 
+  onCompilationUnit {
+      outputDir.set(file("src-gen/main/java/")) // TODO not working yet
+    // Overwrite some options here for single CompilationUnit if needed
+  }
+
 }
 
 tasks.withType(JavaCompile) {