To get a quick feel for event-sourcing and CQRS just try it out via a platform as a service - such as Serialized.io.
Just register an account (it is free)
Read the guides or check out the developers section.
Download sample apps and start exploring ... or just get started on your first own CQRS-experiment by initialize a best-practise-project-skeleton from a maven archetype:
mvn archetype:generate -DarchetypeGroupId=io.serialized.archetype -DarchetypeArtifactId=serialized-dropwizard-archetype
Easy!