What would be the closest equivalent in Java to a Micro ORM such as Dapper, PetaPoco, Massive or CodingHorror?
I recommend Spring JDBC templates. While it's not a "true" ORM, it's a pleasure to use where Hibernate seems to be an overkill.
sql2o seems like a Dapper alternative - thin wrapper around JDBC
String sql =
"SELECT id, category, duedate " +
"FROM tasks " +
"WHERE category = :category";
Sql2o sql2o = new Sql2o(DB_URL, USER, PASS);
List<Task> tasks = sql2o.createQuery(sql)
.addParameter("category", "foo")
.executeAndFetch(Task.class);
github - https://github.com/aaberg/sql2o
site - http://www.sql2o.org/