Add nullability annotations to smoke-test/spring-boot-smoke-test-property-validation

See gh-46587

smoke-test/spring-boot-smoke-test-property-validation/src/main/java/smoketest/propertyvalidation/SampleProperties.java

@@ -16,6 +16,8 @@
 
 package smoketest.propertyvalidation;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.validation.annotation.Validated;
 
@@ -26,18 +28,18 @@ public class SampleProperties {
 	/**
 	 * Sample host.
 	 */
-	private String host;
+	private @Nullable String host;
 
 	/**
 	 * Sample port.
 	 */
 	private Integer port = 8080;
 
-	public String getHost() {
+	public @Nullable String getHost() {
 		return this.host;
 	}
 
-	public void setHost(String host) {
+	public void setHost(@Nullable String host) {
 		this.host = host;
 	}
 

smoke-test/spring-boot-smoke-test-property-validation/src/main/java/smoketest/propertyvalidation/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@NullMarked
+package smoketest.propertyvalidation;
+
+import org.jspecify.annotations.NullMarked;