Repurposed Kie server having classpath issue with a higher version of com.fasterxml.jackson.core:jackson-databind:2.13..2.2

Question

I have a classpath issue for a repurposed Kie server (a spring boot service based on 2.6.6 spring-boot-starter packages) for rule engine as a service. This service already have a transitive dependency on com.fasterxml.jackson.core:jackson-databind:2.13.2.2 and the version of kie-server-spring-boot-starter-drools that I have tried were 7.53.0.Final to 7.73.0.Final and in here the jackson library version dependency for a plain Kie server (no other libraries used in pom) is 2.11.2. While trying to create the KieServicesClient with a KieServicesConfiguration instance (having url,username, password and set the mardshalling to JSON), there is a request to the Kie-server that look for the ServerInfo followed by few steps and then by JSONMarshalling where it encounters an exception (apparently due to the jackson library version mismatches) and getting a server 500 error. The stacktrace look like this:

Caused by: java.lang.NoSuchFieldError: _typeCache at org.kie.server.api.marshalling.json.FallbackableTypeFactory.withFallbackClassLoader(FallbackableTypeFactory.java:62) at org.kie.server.api.marshalling.json.JSONMarshaller.configureMarshaller(JSONMarshaller.java:295) at org.kie.server.api.marshalling.json.JSONMarshaller.(JSONMarshaller.java:191) at org.kie.server.api.marshalling.json.JSONMarshaller.(JSONMarshaller.java:183) at org.kie.server.api.marshalling.BaseMarshallerBuilder.build(BaseMarshallerBuilder.java:45) at org.kie.server.api.marshalling.MarshallerFactory.getMarshaller(MarshallerFactory.java:50) at org.kie.server.services.impl.marshal.MarshallerHelper.marshal(MarshallerHelper.java:78) at org.kie.server.remote.rest.common.util.RestUtils.createCorrectVariant(RestUtils.java:62) at org.kie.server.remote.rest.common.util.RestUtils.createCorrectVariant(RestUtils.java:51) at org.kie.server.remote.rest.common.resource.KieServerRestImpl.getInfo(KieServerRestImpl.java:106) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:179) at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:96) ... 93 common frames omitted

My objective is to repurpose an existing service which has transitive dependency on jackson version 2.13.2 whereas the latest kie-server-spring-boot-starter-drools library has jackson dependency on a lower version. Probably a standalone lean Kie server with single responsibility is the way to go. I'm looking for any suggestions where I can repurpose the service that I'm trying to overload with rule engine feature. Any suggestions for improvement is appreciated.

thanks

I have tried a plain standalone Kie server were there are no errors and it work as expected. When I try to repurpose a service that has a transitive dependency on a higher version of jackson-databind than that expected for the kie-server-spring-boot-starter-drools library. I have debugged the kie server library and found that JSONMarshaller.java from kie-server-api:7.53.0.Final library has a method

protected void configureMarshaller(Set<Class<?>> classes, ClassLoader classLoader) {}

and on line number 149 there is this code as below which produces an exception (i guess it is due the jackson library version mismatches)

TypeResolverBuilder<?> typer = 
    new DefaultTypeResolverBuilder(DefaultTyping.NON_FINAL) { 
        public boolean useForType(JavaType t) {
            return JSONMarshaller.this.classesSet.contains(t.getRawClass());
        }
    };

Answer 1

If you are lucky, then you may be able to exclude the transitive dependency from kie-server-spring-boot-starter-drools and just use the newer one. Have you tried that?