diff --git a/module/spring-boot-data-elasticsearch/build.gradle b/module/spring-boot-data-elasticsearch/build.gradle
index 0a358304f5e..88a0533b10d 100644
--- a/module/spring-boot-data-elasticsearch/build.gradle
+++ b/module/spring-boot-data-elasticsearch/build.gradle
@@ -51,3 +51,11 @@ dependencies {
 
 	testRuntimeOnly("ch.qos.logback:logback-classic")
 }
+
+tasks.named("compileTestJava") {
+	options.nullability.checking = "tests"
+}
+
+tasks.named("compileDockerTestJava") {
+	options.nullability.checking = "tests"
+}
diff --git a/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/autoconfigure/DataElasticsearchAutoConfigurationTests.java b/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/autoconfigure/DataElasticsearchAutoConfigurationTests.java
index 42aac06ebac..54597238796 100644
--- a/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/autoconfigure/DataElasticsearchAutoConfigurationTests.java
+++ b/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/autoconfigure/DataElasticsearchAutoConfigurationTests.java
@@ -20,6 +20,7 @@ import java.math.BigDecimal;
 import java.util.Collections;
 
 import org.assertj.core.api.InstanceOfAssertFactories;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
@@ -151,7 +152,7 @@ class DataElasticsearchAutoConfigurationTests {
 	static class MyConverter implements Converter<ElasticsearchTemplate, Boolean> {
 
 		@Override
-		public Boolean convert(ElasticsearchTemplate source) {
+		public @Nullable Boolean convert(ElasticsearchTemplate source) {
 			return null;
 		}
 
diff --git a/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/health/DataElasticsearchReactiveHealthIndicatorTests.java b/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/health/DataElasticsearchReactiveHealthIndicatorTests.java
index 1c00a199acf..2d7ce127fe8 100644
--- a/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/health/DataElasticsearchReactiveHealthIndicatorTests.java
+++ b/module/spring-boot-data-elasticsearch/src/test/java/org/springframework/boot/data/elasticsearch/health/DataElasticsearchReactiveHealthIndicatorTests.java
@@ -74,6 +74,7 @@ class DataElasticsearchReactiveHealthIndicatorTests {
 	void elasticsearchIsUp() {
 		setupMockResponse("green");
 		Health health = this.healthIndicator.health().block(TIMEOUT);
+		assertThat(health).isNotNull();
 		assertThat(health.getStatus()).isEqualTo(Status.UP);
 		assertHealthDetailsWithStatus(health.getDetails(), "green");
 	}
@@ -82,6 +83,7 @@ class DataElasticsearchReactiveHealthIndicatorTests {
 	void elasticsearchWithYellowStatusIsUp() {
 		setupMockResponse("yellow");
 		Health health = this.healthIndicator.health().block(TIMEOUT);
+		assertThat(health).isNotNull();
 		assertThat(health.getStatus()).isEqualTo(Status.UP);
 		assertHealthDetailsWithStatus(health.getDetails(), "yellow");
 	}
@@ -91,6 +93,7 @@ class DataElasticsearchReactiveHealthIndicatorTests {
 	void elasticsearchIsDown() throws Exception {
 		this.server.shutdown();
 		Health health = this.healthIndicator.health().block(TIMEOUT);
+		assertThat(health).isNotNull();
 		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
 		assertThat(health.getDetails().get("error")).asString().contains("Connection refused");
 	}
@@ -99,6 +102,7 @@ class DataElasticsearchReactiveHealthIndicatorTests {
 	void elasticsearchIsDownByResponseCode() {
 		this.server.enqueue(new MockResponse().setResponseCode(HttpStatus.INTERNAL_SERVER_ERROR.value()));
 		Health health = this.healthIndicator.health().block(TIMEOUT);
+		assertThat(health).isNotNull();
 		assertThat(health.getStatus()).isEqualTo(Status.DOWN);
 		assertThat(health.getDetails().get("error")).asString().startsWith(ResponseException.class.getName());
 	}
@@ -107,6 +111,7 @@ class DataElasticsearchReactiveHealthIndicatorTests {
 	void elasticsearchIsOutOfServiceByStatus() {
 		setupMockResponse("red");
 		Health health = this.healthIndicator.health().block(TIMEOUT);
+		assertThat(health).isNotNull();
 		assertThat(health.getStatus()).isEqualTo(Status.OUT_OF_SERVICE);
 		assertHealthDetailsWithStatus(health.getDetails(), "red");
 	}