Spring technologies examples:

Modules:

common-model

Example of common module for a few applications
Example of POJO with One-to-many JPA configuration
Used by other modules for DB storage
Have DB data from import.sql. Other SpringBoot applications detect it automatically and execute on start

rest-template-example

Example of spring RestTemplate that able to make REST calls to himself
Example of spring-boot microservice

spring-boot-full-app

Example of sping-boot microservice
Example of spring-data
Example of end-to-end application 
Example of H2 and postgreSQL properties configuration
Example of manual jackson converter
//todo another one microservice. MultiModule one more time?
//todo connect them with Netflix Eureka
//todo connect them with Netflix Feign
//todo integration tests

spring-context-example

Example of java configuration.
Example of DataSource PostgreSQL configuration
Example of JPA repository level: EntityManager, JPQL

spring-eureka-feign-example

Spring boot 2.1 and spring cloud dependency configuration
Example of eureka-feign
Example of ribbon loadBalancer
Example of wrapped RestTemplate to not use http://localhost:3004 but http://ValidationService instead 
Example of two microservices that exhanging data
Example of PathVariable
Example of OpenTracing with Jeager (dependency)
    info on backend dependency https://github.com/opentracing-contrib/java-spring-jaeger
    info about Jeager service https://www.jaegertracing.io/docs/1.8/getting-started/ (you need to run docker image with 8 ports exposed)
    
    docker run -d --name jaeger \
      -e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \
      -p 5775:5775/udp \
      -p 6831:6831/udp \
      -p 6832:6832/udp \
      -p 5778:5778 \
      -p 16686:16686 \
      -p 14268:14268 \
      -p 9411:9411 \
      jaegertracing/all-in-one:1.8
       
//todo   Investigate discovery server with example https://github.com/kbastani/spring-cloud-microservice-example/blob/master/discovery-microservice/src/main/resources/application.yml
        #    serviceUrl:
        #      defaultZone: http://discovery:${server.port}/eureka/
//todo http://localhost:3003/  showing disabled servers that is down as UP
//todo make commong gateway (front controller)

spring-data-rest

//todo example of spring-data-rest
//todo resolve n+1 probllem