In pretty much every single project you will ever work in there will be a need to persist data. Typically you will use things like JPA, Hibernate, and similar APIs. Using these APIs is a huge step forward compared to the good ol' days when we didn't have things like O/R mappings and nice transactional APIs but had to fiddle around with JDBC connections, rolling back transactions, reading from result sets and whatnot.1 But still, pretty much all of the work you do every time you create a repository class for your entities is plumbing. You are creating nothing but boiler plate code. And time spent on boilerplate code is time wasted, because you are writing code that adds no real value but still needs to be tested and maintained.
