Schema definition language
Schema Root type Query Mutation ==> update delete create Subcription ==> upadate
mvn jetty:run
query links{ allLinks{ description url } }
https://www.howtographql.com/graphql-java/1-getting-started/
https://www.pluralsight.com/guides/java-and-j2ee/building-a-graphql-server-with-spring-boot
http://www.baeldung.com/graphql
https://www.eclipse.org/jetty/documentation/9.4.x/jetty-maven-plugin.html#setting-system-properties