Skills: Microservice solution: java 8/11/17, java spring-boot stack (rest controllers, security, data/jpa, cloud, hibernate, ws, actuator, test), java spring-boot reactive stack (webflux, r2dbc)
Monolith solution: j2ee (jpa, jax-ws, jax-rs, jms, ejb), application servers - weblogic, wildfly, tomee, payara, oracle ADF, oracle ESB
Data storages: postgres, mongodb, oracle
Data migration tools: flyway, liquibase
Messaging: active-mq, kafka, nats, hazelcast queues
Streaming data: kafka streams
Distributed in-memory caches: redis, hazelcast
Reporting: POI, jasper reports
Deployment: jenkins, gitlab-ci/cd, docker (compose), docker swarm, kubernates
Monitoring: prometheus/grafana, zabbix
API documentation: spring-doc/swagger, restdocs