How to use both reactive and non reactive MongoDB template on Webflux Application - spring

Question

Currently, I'm developing a springboot webflux app for my project, where I use reactive-mongo-template and other reactive implementations. Now I have a legacy spring boot application that is implemented by WebMvc ( here i dont use the real springboot app. just using the core services implemented with mongoDB configurations) and it's using (normal) mongo-template for its implemented services. In my webflux app I'm trying to use the old services defined in the legacy application.
For that i tried importing the legacy app using component scan (com.a.b.cservice.core.configuration) and got some error. The problem is it wont detect the application correctly and the non-reactive mongo template.
Does the spring support only 1 mongo connection? These are the error logs i got;
[main] WARN o.s.b.w.r.c.AnnotationConfigReactiveWebServerApplicationContext - [] - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mapperDAOSpringConfigurations': Unsatisfied dependency expressed through field 'mongoTemplate'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mongoTemplate' defined in class path resource
[com/a/b/cservice/core/configuration/MongoConfigurations.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.mongodb.core.MongoTemplate]: Factory method 'mongoTemplate' threw exception; nested exception is java.lang.NoSuchMethodError: com.mongodb.connection.ClusterSettings.getDescription()Ljava/lang/String;
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APPLICATION FAILED TO START
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Description:
An attempt was made to call a method that does not exist. The attempt was made from the following location:
com.mongodb.connection.DefaultClusterFactory.createCluster(DefaultClusterFactory.java:182)
The following method did not exist:
com.mongodb.connection.ClusterSettings.getDescription()Ljava/lang/String;
The method's class, com.mongodb.connection.ClusterSettings, is available from the following locations:
jar:file:/C:/Users/abc/.m2/repository/org/mongodb/mongodb-driver-core/4.0.5/mongodb-driver-core-4.0.5.jar!/com/mongodb/connection/ClusterSettings.class
jar:file:/C:/Users/abc/.m2/repository/org/mongodb/mongo-java-driver/3.12.7/mongo-java-driver-3.12.7.jar!/com/mongodb/connection/ClusterSettings.class
The class hierarchy was loaded from the following locations:
com.mongodb.connection.ClusterSettings: file:/C:/Users/abc/.m2/repository/org/mongodb/mongodb-driver-core/4.0.5/mongodb-driver-core-4.0.5.jar
Action:
Correct the classpath of your application so that it contains a single, compatible version of com.mongodb.connection.ClusterSettings
Are there any workaround to work the legacy app with the webflux application with mongoDb? Or do i need to keep it as a seperate micro-service and call the relevent endpoints?

Answer 1

after a few works and searches, I found the issue is not related to Webflux. purely a mongo client collision between legacy application and webflux drivers. so I exclude the drivers from legacy and imported the spring-boot-starter-data-mongodb along with the reactive spring-boot-starter-data-mongodb-reactive version. (both are using the same version 2.3.5.RELEASE).
ps: found the same issue on here Spring boot 2.0.5.RELEASE and mongo 4.0 connection issues