2019
https://www.baeldung.com/spring-boot-ehcache
    https://github.com/eugenp/tutorials/tree/master/spring-ehcache
https://springframework.guru/using-ehcache-3-in-spring-boot/
2018
https://www.baeldung.com/ehcache
https://github.com/eugenp/tutorials/blob/master/spring-ehcache/src/main/java/com/baeldung/cachetest/config/CacheEventLogger.java
2017
https://memorynotfound.com/spring-caching-example-java-xml-configuration/
2015
https://www.mkyong.com/spring/spring-caching-and-ehcache-example/