diff --git a/smoke-test/spring-boot-smoke-test-session-hazelcast/build.gradle b/smoke-test/spring-boot-smoke-test-session-hazelcast/build.gradle
index f280c138506..b3f89142abb 100644
--- a/smoke-test/spring-boot-smoke-test-session-hazelcast/build.gradle
+++ b/smoke-test/spring-boot-smoke-test-session-hazelcast/build.gradle
@@ -29,3 +29,7 @@ dependencies {
 	testImplementation(project(":starter:spring-boot-starter-webmvc-test"))
 	testImplementation(project(":starter:spring-boot-starter-test"))
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/smoke-test/spring-boot-smoke-test-session-hazelcast/src/test/java/smoketest/session/hazelcast/SampleSessionHazelcastApplicationTests.java b/smoke-test/spring-boot-smoke-test-session-hazelcast/src/test/java/smoketest/session/hazelcast/SampleSessionHazelcastApplicationTests.java
index d6884f57f7f..30d7c4aef7f 100644
--- a/smoke-test/spring-boot-smoke-test-session-hazelcast/src/test/java/smoketest/session/hazelcast/SampleSessionHazelcastApplicationTests.java
+++ b/smoke-test/spring-boot-smoke-test-session-hazelcast/src/test/java/smoketest/session/hazelcast/SampleSessionHazelcastApplicationTests.java
@@ -61,20 +61,20 @@ class SampleSessionHazelcastApplicationTests {
 		ResponseEntity<Map<String, Object>> entity = getSessions();
 		assertThat(entity).isNotNull();
 		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
-		List<Map<String, Object>> sessions = (List<Map<String, Object>>) entity.getBody().get("sessions");
+		Map<String, Object> body = entity.getBody();
+		assertThat(body).isNotNull();
+		List<Map<String, Object>> sessions = (List<Map<String, Object>>) body.get("sessions");
 		assertThat(sessions).hasSize(1);
 	}
 
-	private String performLogin() {
+	private void performLogin() {
 		HttpHeaders headers = new HttpHeaders();
 		headers.setAccept(Collections.singletonList(MediaType.TEXT_HTML));
 		headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
 		MultiValueMap<String, String> form = new LinkedMultiValueMap<>();
 		form.set("username", "user");
 		form.set("password", "password");
-		ResponseEntity<String> entity = this.restTemplate.exchange("/login", HttpMethod.POST,
-				new HttpEntity<>(form, headers), String.class);
-		return entity.getHeaders().getFirst("Set-Cookie");
+		this.restTemplate.exchange("/login", HttpMethod.POST, new HttpEntity<>(form, headers), String.class);
 	}
 
 	private ResponseEntity<Map<String, Object>> getSessions() {