Spring Boot GraphQL Server with embedded Keycloak instance wont start - spring-boot

Question

what I am actually trying is, to built an backend with Spring Boot, this backend is split into two modules. One auth-server (embedded keycloak-server) and one resource-server (graphql-server).
In there I've a so service, called KeycloakService. This service has many public methods to communicate with the embedded keycloak instance. Every method has a meaningful equivalent in the graphql schema to create the possibility, to e.g. create new users or roles over a graphql mutation.
The auth-server runs without any problems.
But when I start up the resource server it crashes with the following stacktrace:
It tells me that he couldnt find TestLdapConnectionRepresentation.class, but I dont understand why he is trying to search for it, because I never used this feature of Keycloak.
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'keycloakService' defined in file [C:\Users\User\IdeaProjects\software\backend\resource-server\target\classes\com\software\backend\resource\services\KeycloakService.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.software.backend.resource.services.KeycloakService]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/keycloak/representations/idm/TestLdapConnectionRepresentation
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1320) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1214) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:885) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:789) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
... 159 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.software.backend.resource.services.KeycloakService]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/keycloak/representations/idm/TestLdapConnectionRepresentation
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:213) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1312) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
... 171 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/keycloak/representations/idm/TestLdapConnectionRepresentation
at java.base/java.lang.Class.getDeclaredMethods0(Native Method) ~[na:na]
at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3244) ~[na:na]
at java.base/java.lang.Class.privateGetPublicMethods(Class.java:3269) ~[na:na]
at java.base/java.lang.Class.getMethods(Class.java:1918) ~[na:na]
at org.jboss.resteasy.client.jaxrs.ProxyBuilder.proxy(ProxyBuilder.java:57) ~[resteasy-client-3.9.1.Final.jar:3.9.1.Final]
at org.jboss.resteasy.client.jaxrs.internal.proxy.SubResourceInvoker.invoke(SubResourceInvoker.java:67) ~[resteasy-client-3.9.1.Final.jar:3.9.1.Final]
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientProxy.invoke(ClientProxy.java:76) ~[resteasy-client-3.9.1.Final.jar:3.9.1.Final]
at com.sun.proxy.$Proxy107.realm(Unknown Source) ~[na:na]
at org.keycloak.admin.client.Keycloak.realm(Keycloak.java:114) ~[keycloak-admin-client-10.0.0.jar:10.0.0]
at com.software.backend.resource.services.KeycloakService.<init>(KeycloakService.java:29) ~[classes/:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) ~[na:na]
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481) ~[na:na]
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:200) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
... 173 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.keycloak.representations.idm.TestLdapConnectionRepresentation
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602) ~[na:na]
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[na:na]
... 189 common frames omitted
Process finished with exit code 0
This not the complete stacktrace, but because of StackOverflows char limitation, I only publish the line which I think what are important. If you need some more information, to be able to help me. Let me know.
Hopefully there is someone out there, who can help me.

Answer 1

Had the same problem and it seems Gradle does not resolve the "keycloak-core" dependency correctly (resolves version 8.0.1):
$ gradlew -q dependencies
...
\--- org.keycloak:keycloak-admin-client:11.0.2
+--- org.keycloak:keycloak-core:11.0.2 -> 8.0.1
...
I also added the "keycloak-core" dependency directly into my project which solved the problem:
dependencies {
implementation 'org.keycloak:keycloak-core:11.0.2'
implementation 'org.keycloak:keycloak-admin-client:11.0.2'
}
$ ./gradlew -q dependencies
...
\--- org.keycloak:keycloak-admin-client:11.0.2
+--- org.keycloak:keycloak-core:11.0.2
...