Spring-boot and Keycloak Integration

Question

I am using spring boot 2.1.7 Release and keycloak-spring-boot-2-starter:4.0.0.Final version. This keycloak-spring-boot-2-starter automatically downloads required keycloak adapter dependencies corresponding to 4.0.0.Final release of keycloak adapter dependencies. Now when I am calling the keycloak protected resource(The rest api which needs to be authorized by keycloak server), I am getting the following error:-

java.lang.RuntimeException: Could not obtain configuration from server [http://localhost:8180/auth/realms/mint/.well-known/uma2-configuration].
    at org.keycloak.authorization.client.AuthzClient.<init>(AuthzClient.java:242) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.authorization.client.AuthzClient.create(AuthzClient.java:85) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.authorization.PolicyEnforcer.<init>(PolicyEnforcer.java:66) ~[keycloak-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.KeycloakDeploymentBuilder.internalBuild(KeycloakDeploymentBuilder.java:143) ~[keycloak-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.KeycloakDeploymentBuilder.build(KeycloakDeploymentBuilder.java:169) ~[keycloak-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.springboot.KeycloakSpringBootConfigResolver.resolve(KeycloakSpringBootConfigResolver.java:37) ~[keycloak-spring-boot-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.AdapterDeploymentContext.resolveDeployment(AdapterDeploymentContext.java:88) ~[keycloak-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.PreAuthActionsHandler.preflightCors(PreAuthActionsHandler.java:107) ~[keycloak-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.PreAuthActionsHandler.handleRequest(PreAuthActionsHandler.java:79) ~[keycloak-adapter-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.adapters.tomcat.AbstractKeycloakAuthenticatorValve.invoke(AbstractKeycloakAuthenticatorValve.java:177) ~[spring-boot-container-bundle-4.0.0.Final.jar:4.0.0.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1747) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_221]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_221]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.19.jar:9.0.19]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_221]
Caused by: java.lang.RuntimeException: Error executing http method [RequestBuilder [method=GET, charset=UTF-8, version=null, uri=http://localhost:8180/auth/realms/mint/.well-known/uma2-configuration, headerGroup=null, entity=null, parameters=null, config=null]]. Response : [B@1aa5d283
    at org.keycloak.authorization.client.util.HttpMethod.execute(HttpMethod.java:106) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.authorization.client.util.HttpMethodResponse$2.execute(HttpMethodResponse.java:50) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.authorization.client.AuthzClient.<init>(AuthzClient.java:240) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    ... 22 common frames omitted
Caused by: java.lang.RuntimeException: Error parsing JSON response.
    at org.keycloak.authorization.client.util.HttpMethodResponse$2$1.process(HttpMethodResponse.java:56) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.authorization.client.util.HttpMethod.execute(HttpMethod.java:102) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    ... 24 common frames omitted
Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "introspection_endpoint" (class org.keycloak.authorization.client.representation.ServerConfiguration), not marked as ignorable (27 known properties: "end_session_endpoint", "check_session_iframe", "grant_types_supported", "scopes_supported", "claims_parameter_supported", "userinfo_signing_alg_values_supported", "subject_types_supported", "authorization_endpoint", "request_object_signing_alg_values_supported", "token_introspection_endpoint", "response_modes_supported", "jwks_uri", "claim_types_supported", "claims_supported", "request_parameter_supported", "response_types_supported", "token_endpoint_auth_methods_supported", "id_token_signing_alg_values_supported", "issuer", "policy_endpoint", "permission_endpoint", "request_uri_parameter_supported", "token_endpoint", "token_endpoint_auth_signing_alg_values_supported", "resource_registration_endpoint", "userinfo_endpoint", "registration_endpoint"])
 at [Source: (byte[])"{"issuer":"http://localhost:8180/auth/realms/mint","authorization_endpoint":"http://localhost:8180/auth/realms/mint/protocol/openid-connect/auth","token_endpoint":"http://localhost:8180/auth/realms/mint/protocol/openid-connect/token","token_introspection_endpoint":"http://localhost:8180/auth/realms/mint/protocol/openid-connect/token/introspect","end_session_endpoint":"http://localhost:8180/auth/realms/mint/protocol/openid-connect/logout","jwks_uri":"http://localhost:8180/auth/realms/mint/protoco"[truncated 1119 bytes]; line: 1, column: 1539] (through reference chain: org.keycloak.authorization.client.representation.ServerConfiguration["introspection_endpoint"])
    at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:61) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:823) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1153) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1589) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1567) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:294) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4013) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3091) ~[jackson-databind-2.9.8.jar:2.9.8]
    at org.keycloak.util.JsonSerialization.readValue(JsonSerialization.java:69) ~[keycloak-core-4.0.0.Final.jar:4.0.0.Final]
    at org.keycloak.authorization.client.util.HttpMethodResponse$2$1.process(HttpMethodResponse.java:54) ~[keycloak-authz-client-4.0.0.Final.jar:4.0.0.Final]
    ... 25 common frames omitted

When I decompiled the ServerConfiguration.class from the keycloak-authz-client-4.0.0.Final.jar jar, I could see that there is no such property as "introspection_endpoint" which is why the application is throwing the error of 'Unrecognized field "introspection_endpoint"'.

When I looked into the relatively lower version of keycloak-authz-client ie keycloak-authz-client-3.3.0.Final.jar, I could see that "introspection_endpoint" property is present. So it appears that this property was dropped somewhere in the upper versions such as keycloak-authz-client-4.0.0.Final.jar, keycloak-authz-client-4.0.0.Beta2.jar.etc.

So I thought of using keycloak-spring-boot-starter rather than keycloak-spring-boot-2- and inject the respective version of keycloak adapter BOM. I manually included the following dependencies:-

compile "org.keycloak:keycloak-spring-boot-starter:3.3.0.Final"
compile "org.keycloak:keycloak-spring-boot-adapter:3.3.0.Final"
compile "org.keycloak:keycloak-authz-client:3.3.0.Final"
compile "org.keycloak:keycloak-spring-security-adapter:3.3.0.Final"
compile "org.keycloak:keycloak-spring-boot-adapter:3.3.0.Final"
compile "org.keycloak:keycloak-core:3.3.0.Final"
compile "org.keycloak:keycloak-adapter-spi:3.3.0.Final"
compile "org.keycloak:keycloak-adapter-core:3.3.0.Final"
compile "org.keycloak:keycloak-common:3.3.0.Final"

But now when I am trying to run the spring boot application, it exits with the following error:-

java.lang.IllegalStateException: Error processing condition on org.springframework.boot.actuate.autoconfigure.audit.AuditAutoConfiguration$AuditEventRepositoryConfiguration
    at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:60) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:108) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader$TrackedConditionEvaluator.shouldSkip(ConfigurationClassBeanDefinitionReader.java:447) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:128) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:117) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:327) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:232) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:275) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:95) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:705) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:531) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:743) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:390) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:312) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1214) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1203) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at com.azilen.micro.api.gateway.MintApiGateway.main(MintApiGateway.java:19) [main/:na]
Caused by: java.lang.IllegalStateException: Failed to introspect Class [org.keycloak.adapters.springboot.KeycloakAutoConfiguration] from ClassLoader [sun.misc.Launcher$AppClassLoader@764c12b6]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:507) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:404) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:389) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:447) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) ~[na:1.8.0_221]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:738) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:679) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:647) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1518) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1023) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry.addBeanTypeForNonAliasDefinition(BeanTypeRegistry.java:189) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry.addBeanTypeForNonAliasDefinition(BeanTypeRegistry.java:156) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry.addBeanType(BeanTypeRegistry.java:149) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry.updateTypesIfNecessary(BeanTypeRegistry.java:137) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at java.util.Iterator.forEachRemaining(Iterator.java:116) ~[na:1.8.0_221]
    at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry.updateTypesIfNecessary(BeanTypeRegistry.java:132) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry.getNamesForType(BeanTypeRegistry.java:96) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.collectBeanNamesForType(OnBeanCondition.java:269) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getBeanNamesForType(OnBeanCondition.java:262) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getBeanNamesForType(OnBeanCondition.java:251) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchingBeans(OnBeanCondition.java:171) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.OnBeanCondition.getMatchOutcome(OnBeanCondition.java:145) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:47) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    ... 17 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/springframework/boot/context/embedded/EmbeddedServletContainerCustomizer
    at java.lang.Class.getDeclaredMethods0(Native Method) ~[na:1.8.0_221]
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[na:1.8.0_221]
    at java.lang.Class.getDeclaredMethods(Class.java:1975) ~[na:1.8.0_221]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:489) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    ... 39 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382) ~[na:1.8.0_221]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_221]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349) ~[na:1.8.0_221]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_221]
    ... 43 common frames omitted

2019-09-09 18:13:24.553  WARN 28792 --- [           main] o.s.boot.SpringApplication               : Unable to close ApplicationContext

java.lang.IllegalStateException: Failed to introspect Class [org.keycloak.adapters.springboot.KeycloakAutoConfiguration] from ClassLoader [sun.misc.Launcher$AppClassLoader@764c12b6]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:507) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:404) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:389) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.util.ReflectionUtils.getUniqueDeclaredMethods(ReflectionUtils.java:447) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) ~[na:1.8.0_221]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryMethod(AbstractAutowireCapableBeanFactory.java:738) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:679) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:647) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1518) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:511) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:481) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:602) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:594) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBeansOfType(AbstractApplicationContext.java:1226) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.boot.SpringApplication.getExitCodeFromMappedException(SpringApplication.java:865) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.getExitCodeFromException(SpringApplication.java:853) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.handleExitCode(SpringApplication.java:840) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.handleRunFailure(SpringApplication.java:791) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:322) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1214) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1203) [spring-boot-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at com.azilen.micro.api.gateway.MintApiGateway.main(MintApiGateway.java:19) [main/:na]
Caused by: java.lang.NoClassDefFoundError: org/springframework/boot/context/embedded/EmbeddedServletContainerCustomizer
    at java.lang.Class.getDeclaredMethods0(Native Method) ~[na:1.8.0_221]
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) ~[na:1.8.0_221]
    at java.lang.Class.getDeclaredMethods(Class.java:1975) ~[na:1.8.0_221]
    at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:489) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    ... 21 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382) ~[na:1.8.0_221]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_221]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349) ~[na:1.8.0_221]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_221]
    ... 25 common frames omitted

Note:- It appears that the spring boot version and keycloak adapter are not compatible to each other.

Has anyone faced this issue before?

One solution/workaround that I can think off is to edit the ServerConfiguration.class of keycloak-authz-client-4.0.0.Final.jar and add the "introspection_endpoint".

Request you to please advise if anyone has faced a similar issue.

I am using the following versions:- oracle jdk - 1.8 Spring-boot - 2.1.7.RELEASE spring-cloud-dependencies:Greenwich.SR2 Keycloak - 7.0.0

Thank You

Answer 1

I think your problem is in the dependencies declaration, as you can see in keycloak documentation , the liobrary that you have use is org.keycloak:keycloak-spring-boot-starter. This package include all you need to use keycloak, also include keycloak-authz-client which is required for authorization token. If you include this library, you would remove all dependecies that you tokd above:

compile "org.keycloak:keycloak-spring-boot-starter:3.3.0.Final"
compile "org.keycloak:keycloak-spring-boot-adapter:3.3.0.Final"
compile "org.keycloak:keycloak-authz-client:3.3.0.Final"
compile "org.keycloak:keycloak-spring-security-adapter:3.3.0.Final"
compile "org.keycloak:keycloak-spring-boot-adapter:3.3.0.Final"
compile "org.keycloak:keycloak-core:3.3.0.Final"
compile "org.keycloak:keycloak-adapter-spi:3.3.0.Final"
compile "org.keycloak:keycloak-adapter-core:3.3.0.Final"
compile "org.keycloak:keycloak-common:3.3.0.Final"

Answer 2

2022 update

Keycloak adapters are no longer supported: https://www.keycloak.org/2022/02/adapter-deprecation.html

As an alternate for resource-servers (REST APIs), you can use either:

• spring-boot-starter-oauth2-resource-server : https://github.com/ch4mpy/spring-addons/blob/master/samples/tutorials/resource-server_with_jwtauthenticationtoken (requires quires quite some Java conf)
• spring-addons-webmvc-jwt-resource-server : https://github.com/ch4mpy/spring-addons/tree/master/samples/tutorials/resource-server_with_oauthentication (a lot of config from properties, including CORS and roles mapping)