NullPointerException on startup

[davgia]

Describe the bug
I have updated my java microservices (Java 17, Boot: 3.1.0, Cloud: 2022.0.2) to the latest available version of Spring Boot (3.4.1) and Spring Cloud (2024.0.0) and to Java 21. The spring application works fine locally and with my docker-compose test configuration. Deployed on Kubernetes it fails to startup with the following error:

12:07:07.633 [main] ERROR org.springframework.boot.SpringApplication -- Application run failed
java.lang.NullPointerException: Cannot invoke "org.springframework.cloud.kubernetes.commons.KubernetesClientProperties.withNamespace(String)" because the return value of "org.springframework.boot.ConfigurableBootstrapContext.get(java.lang.Class)" is null
    at org.springframework.cloud.kubernetes.commons.config.KubernetesConfigDataLocationResolver$PropertyHolder.clientProperties(KubernetesConfigDataLocationResolver.java:181)
    at org.springframework.cloud.kubernetes.commons.config.KubernetesConfigDataLocationResolver$PropertyHolder.of(KubernetesConfigDataLocationResolver.java:167)
    at org.springframework.cloud.kubernetes.commons.config.KubernetesConfigDataLocationResolver.resolveProfileSpecific(KubernetesConfigDataLocationResolver.java:89)
    at org.springframework.boot.context.config.ConfigDataLocationResolvers.lambda$resolve$2(ConfigDataLocationResolvers.java:107)
    at org.springframework.boot.context.config.ConfigDataLocationResolvers.resolve(ConfigDataLocationResolvers.java:113)
    at org.springframework.boot.context.config.ConfigDataLocationResolvers.resolve(ConfigDataLocationResolvers.java:106)
    at org.springframework.boot.context.config.ConfigDataLocationResolvers.resolve(ConfigDataLocationResolvers.java:94)
    at org.springframework.boot.context.config.ConfigDataImporter.resolve(ConfigDataImporter.java:106)
    at org.springframework.boot.context.config.ConfigDataImporter.resolve(ConfigDataImporter.java:98)
    at org.springframework.boot.context.config.ConfigDataImporter.resolveAndLoad(ConfigDataImporter.java:86)
    at org.springframework.boot.context.config.ConfigDataEnvironmentContributors.withProcessedImports(ConfigDataEnvironmentContributors.java:121)
    at org.springframework.boot.context.config.ConfigDataEnvironment.processWithProfiles(ConfigDataEnvironment.java:316)
    at org.springframework.boot.context.config.ConfigDataEnvironment.processAndApply(ConfigDataEnvironment.java:237)
    at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:96)
    at org.springframework.boot.context.config.ConfigDataEnvironmentPostProcessor.postProcessEnvironment(ConfigDataEnvironmentPostProcessor.java:89)
    at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEnvironmentPreparedEvent(EnvironmentPostProcessorApplicationListener.java:132)
    at org.springframework.boot.env.EnvironmentPostProcessorApplicationListener.onApplicationEvent(EnvironmentPostProcessorApplicationListener.java:115)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:185)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:178)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:156)
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:138)
    at org.springframework.boot.context.event.EventPublishingRunListener.multicastInitialEvent(EventPublishingRunListener.java:136)
    at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:81)
    at org.springframework.boot.SpringApplicationRunListeners.lambda$environmentPrepared$2(SpringApplicationRunListeners.java:64)
    at java.base/java.lang.Iterable.forEach(Iterable.java:75)
    at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:118)
    at org.springframework.boot.SpringApplicationRunListeners.doWithListeners(SpringApplicationRunListeners.java:112)
    at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:63)
    at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:353)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:313)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1361)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1350)
    at com.example.demo.DemoApplication.main(DemoApplication.java:10)
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
    at java.base/java.lang.reflect.Method.invoke(Method.java:580)
    at org.springframework.boot.loader.launch.Launcher.launch(Launcher.java:102)
    at org.springframework.boot.loader.launch.Launcher.launch(Launcher.java:64)
    at org.springframework.boot.loader.launch.JarLauncher.main(JarLauncher.java:40)

Sample
This is a sample of a spring cloud gateway webflux application. I've included both Dockerfile and k8s manifests to test it.

demo.zip

Linked issues
This issues it is probably related to #1654.

[wind57]

it's a bug, thank you for your report. Its very similar indeed to the linked one.

@ryanjbaxter can you add the bug label please? I will see how to fix it..

[ryanjbaxter]

I was litterally just looking at this issue :). Seems like you were just ahead of me

[wind57]

yeah, its the same dependency thing we had in the past in the linked issue. In Fabric8ConfigServerBootstrapper we do :

		registry.registerIfAbsent(KubernetesClientProperties.class, context -> {
			if (!getDiscoveryEnabled(context)) {
				return null;
			}
			return createKubernetesClientProperties(context);
		});

so we register a "null" but later try to do something with that one. I will take a look closer on it in the upcoming days