--- a/spring-oxm/spring-oxm.gradle
+++ b/spring-oxm/spring-oxm.gradle
@@ -2,6 +2,8 @@ plugins {
 	id "org.unbroken-dome.xjc"
 }
 
+apply plugin: "com.github.johnrengelman.shadow"
+
 description = "Spring Object/XML Marshalling"
 
 xjc {
@@ -19,7 +21,7 @@ dependencies {
 	api(project(":spring-core"))
 	optional("jakarta.xml.bind:jakarta.xml.bind-api")
 	optional("jakarta.activation:jakarta.activation-api")
-	optional("com.thoughtworks.xstream:xstream")
+	implementation("com.thoughtworks.xstream:xstream")
 	testImplementation(project(":spring-context"))
 	testImplementation(testFixtures(project(":spring-core")))
 	testImplementation("org.codehaus.jettison:jettison") {