Upgrade to Nullability Plugin 0.0.11

In addition to the upgrade, this commit also fixes some contract
violations in non-public APIs that are now detected as the new
version of the plugin enables contract checking by default.

Closes gh-49000

gradle.properties

@@ -19,7 +19,7 @@ kotlinVersion=2.2.21
 mavenVersion=3.9.10
 mockitoVersion=5.20.0
 nativeBuildToolsVersion=0.11.4
-nullabilityPluginVersion=0.0.10
+nullabilityPluginVersion=0.0.11
 snakeYamlVersion=2.5
 springFrameworkVersion=7.0.3
 springFramework60xVersion=6.0.23

module/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/web/server/ManagementServerProperties.java

@@ -107,10 +107,10 @@ public class ManagementServerProperties {
 
 	@Contract("!null -> !null")
 	private @Nullable String cleanBasePath(@Nullable String basePath) {
-		String candidate = null;
-		if (StringUtils.hasLength(basePath)) {
-			candidate = basePath.strip();
+		if (basePath == null) {
+			return null;
 		}
+		String candidate = basePath.strip();
 		if (StringUtils.hasText(candidate)) {
 			if (!candidate.startsWith("/")) {
 				candidate = "/" + candidate;

module/spring-boot-web-server/src/main/java/org/springframework/boot/web/server/context/SpringBootTestRandomPortContextCustomizer.java

@@ -111,7 +111,7 @@ class SpringBootTestRandomPortContextCustomizer implements ContextCustomizer {
 		private static final Integer ZERO = Integer.valueOf(0);
 
 		boolean isFixed(MapPropertySource source, Port port) {
-			return !ZERO.equals(get(source, port, null));
+			return !ZERO.equals(get(source, port));
 		}
 
 		boolean isConfigured(PropertySource<?> source, Port port) {
@@ -121,14 +121,13 @@ class SpringBootTestRandomPortContextCustomizer implements ContextCustomizer {
 		@Contract("_, _, !null -> !null")
 		@Nullable Integer get(PropertySources sources, Port port, @Nullable Integer defaultValue) {
 			return sources.stream()
-				.map((source) -> get(source, port, defaultValue))
+				.map((source) -> get(source, port))
 				.filter(Objects::nonNull)
 				.findFirst()
 				.orElse(defaultValue);
 		}
 
-		@Contract("_, _, !null -> !null")
-		@Nullable Integer get(PropertySource<?> source, Port port, @Nullable Integer defaultValue) {
+		@Nullable Integer get(PropertySource<?> source, Port port) {
 			Object value = source.getProperty(port.property());
 			if (value == null || ClassUtils.isAssignableValue(Integer.class, value)) {
 				return (Integer) value;