Spring Boot Rest API failed to run if actuator dependency is added to pom.xml-CodePudding

I have a simple spring boot application with just one GET endpoint for testing purpose. The endpoint works fine as far as I don't add the actuator dependency to my project. However, as soon as I add the actuator dependency, it stops running and throws the following error which is surprisingly for swagger I believe.

So I am not understanding why this error is appearing if I have swagger already enabled and working.

Error:

2022-10-02 22:48:26.558  WARN 14872 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
2022-10-02 22:48:26.739  INFO 14872 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2022-10-02 22:48:26.754  INFO 14872 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-10-02 22:48:26.769 ERROR 14872 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.context.ApplicationContextException: Failed to start bean 'documentationPluginsBootstrapper'; nested exception is java.lang.NullPointerException
    at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.23.jar:5.3.23]
    at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.23.jar:5.3.23]
    at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.23.jar:5.3.23]
    at java.base/java.lang.Iterable.forEach(Iterable.java:75) ~[na:na]
    at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.23.jar:5.3.23]
    at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.23.jar:5.3.23]
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.23.jar:5.3.23]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.23.jar:5.3.23]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:147) ~[spring-boot-2.7.4.jar:2.7.4]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:734) ~[spring-boot-2.7.4.jar:2.7.4]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:408) ~[spring-boot-2.7.4.jar:2.7.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.4.jar:2.7.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.7.4.jar:2.7.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1295) ~[spring-boot-2.7.4.jar:2.7.4]
    at com.example.playground.PlaygroundApplication.main(PlaygroundApplication.java:10) ~[classes/:na]
Caused by: java.lang.NullPointerException: null
    at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:112) ~[springfox-spi-2.9.2.jar:null]
    at springfox.documentation.spi.service.contexts.Orderings$8.compare(Orderings.java:109) ~[springfox-spi-2.9.2.jar:null]
    at com.google.common.collect.ComparatorOrdering.compare(ComparatorOrdering.java:37) ~[guava-20.0.jar:na]
    at java.base/java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) ~[na:na]
    at java.base/java.util.TimSort.sort(TimSort.java:220) ~[na:na]
    at java.base/java.util.Arrays.sort(Arrays.java:1441) ~[na:na]
    at com.google.common.collect.Ordering.sortedCopy(Ordering.java:855) ~[guava-20.0.jar:na]
    at springfox.documentation.spring.web.plugins.WebMvcRequestHandlerProvider.requestHandlers(WebMvcRequestHandlerProvider.java:57) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:138) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper$2.apply(DocumentationPluginsBootstrapper.java:135) ~[springfox-spring-web-2.9.2.jar:null]
    at com.google.common.collect.Iterators$7.transform(Iterators.java:750) ~[guava-20.0.jar:na]
    at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) ~[guava-20.0.jar:na]
    at com.google.common.collect.TransformedIterator.next(TransformedIterator.java:47) ~[guava-20.0.jar:na]
    at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:52) ~[guava-20.0.jar:na]
    at com.google.common.collect.MultitransformedIterator.hasNext(MultitransformedIterator.java:50) ~[guava-20.0.jar:na]
    at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:249) ~[guava-20.0.jar:na]
    at com.google.common.collect.ImmutableList.copyOf(ImmutableList.java:209) ~[guava-20.0.jar:na]
    at com.google.common.collect.FluentIterable.toList(FluentIterable.java:614) ~[guava-20.0.jar:na]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.defaultContextBuilder(DocumentationPluginsBootstrapper.java:111) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.buildContext(DocumentationPluginsBootstrapper.java:96) ~[springfox-spring-web-2.9.2.jar:null]
    at springfox.documentation.spring.web.plugins.DocumentationPluginsBootstrapper.start(DocumentationPluginsBootstrapper.java:167) ~[springfox-spring-web-2.9.2.jar:null]
    at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.23.jar:5.3.23]
    ... 14 common frames omitted

Here is this sample project in the github that you can clone and run to replicate this error: https://github.com/syednoman84/playground/

Few points about this sample project:

It is using actuator, lombok, swagger2, swagger-ui and swagger-bean-validators
I have this spring.mvc.pathmatch.matching-strategy=ANT_PATH_MATCHER in my application.properties
I have a SwaggerConfig defined in SwaggerConfig.java
I have a DocketApiBean defined as DocketApiBean.java

Just to reiterate, as soon as I remove the actuator dependency from my pom.xml, everything works fine. However, if I add the actuator dependency and then run the app, it fails to start.

Thanks for the help in advance.

CodePudding user response：

Swaggerfox is not compatible with the newer Spring Boot versions.

Try Springdoc instead https://springdoc.org/:

<dependency>
      <groupId>org.springdoc</groupId>
      <artifactId>springdoc-openapi-ui</artifactId>
      <version>1.6.11</version>
 </dependency>

You can access the Swagger UI: http://localhost:8080/swagger-ui/index.html