diff --git a/smoke-test/spring-boot-smoke-test-jackson2-mixed/build.gradle b/smoke-test/spring-boot-smoke-test-jackson2-mixed/build.gradle
index 51a0f1b4010f..658c466fa094 100644
--- a/smoke-test/spring-boot-smoke-test-jackson2-mixed/build.gradle
+++ b/smoke-test/spring-boot-smoke-test-jackson2-mixed/build.gradle
@@ -27,3 +27,7 @@ dependencies {
 
 	testImplementation(project(":starter:spring-boot-starter-webmvc-test"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/smoke-test/spring-boot-smoke-test-jackson2-only/build.gradle b/smoke-test/spring-boot-smoke-test-jackson2-only/build.gradle
index b944b91bca00..c4aeeee91da1 100644
--- a/smoke-test/spring-boot-smoke-test-jackson2-only/build.gradle
+++ b/smoke-test/spring-boot-smoke-test-jackson2-only/build.gradle
@@ -32,3 +32,7 @@ dependencies {
 	}
 	testImplementation(project(":test-support:spring-boot-test-support"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/smoke-test/spring-boot-smoke-test-jackson2-only/src/test/java/smoketest/jackson2/only/JsonPojo.java b/smoke-test/spring-boot-smoke-test-jackson2-only/src/test/java/smoketest/jackson2/only/JsonPojo.java
index 4f0727eddabf..d6aacf87e2bc 100644
--- a/smoke-test/spring-boot-smoke-test-jackson2-only/src/test/java/smoketest/jackson2/only/JsonPojo.java
+++ b/smoke-test/spring-boot-smoke-test-jackson2-only/src/test/java/smoketest/jackson2/only/JsonPojo.java
@@ -16,6 +16,8 @@
 
 package smoketest.jackson2.only;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * POJO for serialization to JSON.
  *
@@ -23,23 +25,23 @@
  */
 class JsonPojo {
 
-	private String alpha;
+	private @Nullable String alpha;
 
-	private String bravo;
+	private @Nullable String bravo;
 
-	String getAlpha() {
+	@Nullable String getAlpha() {
 		return this.alpha;
 	}
 
-	void setAlpha(String alpha) {
+	void setAlpha(@Nullable String alpha) {
 		this.alpha = alpha;
 	}
 
-	String getBravo() {
+	@Nullable String getBravo() {
 		return this.bravo;
 	}
 
-	void setBravo(String bravo) {
+	void setBravo(@Nullable String bravo) {
 		this.bravo = bravo;
 	}
 
diff --git a/smoke-test/spring-boot-smoke-test-jersey/build.gradle b/smoke-test/spring-boot-smoke-test-jersey/build.gradle
index 4c7e3a21c0f8..d31a5d7e88f4 100644
--- a/smoke-test/spring-boot-smoke-test-jersey/build.gradle
+++ b/smoke-test/spring-boot-smoke-test-jersey/build.gradle
@@ -30,3 +30,7 @@ dependencies {
 	testImplementation(project(":starter:spring-boot-starter-jersey-test"))
 	testImplementation(project(":module:spring-boot-restclient"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/smoke-test/spring-boot-smoke-test-log4j2/build.gradle b/smoke-test/spring-boot-smoke-test-log4j2/build.gradle
index 1478949bf7c5..14f96900bfb2 100644
--- a/smoke-test/spring-boot-smoke-test-log4j2/build.gradle
+++ b/smoke-test/spring-boot-smoke-test-log4j2/build.gradle
@@ -32,3 +32,7 @@ dependencies {
 
 	testImplementation(project(":starter:spring-boot-starter-test"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/smoke-test/spring-boot-smoke-test-secure-jersey/build.gradle b/smoke-test/spring-boot-smoke-test-secure-jersey/build.gradle
index a49dcbb1b1a2..c3ea4f67dd40 100644
--- a/smoke-test/spring-boot-smoke-test-secure-jersey/build.gradle
+++ b/smoke-test/spring-boot-smoke-test-secure-jersey/build.gradle
@@ -28,3 +28,7 @@ dependencies {
 	testImplementation(project(":starter:spring-boot-starter-jersey-test"))
 	testImplementation(project(":module:spring-boot-restclient"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}