I know that the RoR can do the CRUD easily, but is there any similar framework in Java to make the CRUD easy instead of typing boring SQL statement?
Hibernate is usually recommended for Java.
Note that Grails is the Java equivalent of RoR and can use GORM (Grails Object-Relational-Mapping - a Groovy interface over Hibernate) or Hibernate directly. So if you're coming from the RoR world, perhaps checking out Grails will be useful.
Are you looking for a way to map data to objects and back (Object-Relational Mapping, commonly abbreviated to ORM or OR/M) or way to automate CRUD operations to a set of data? These two are connected, however the answers may change slightly depending on your actual goal.
For example, automated OR/M can be done with anything that supports Java Persistence API. Hibernate is a good bet for this because it's actually the origin of the JPA.
CRUD handling however means more than just storing data, it relates to user priviledges and dynamic creation of views for the four operations too; OR/M is just a subset of CRUD.
Play Framework is the pure Java framework to make CRUD easy. Maybe you want to try it out.
Grails has a lot in common with Ruby on Rails (it was originally know as Groovy on Rails), providing the scaffolding and supports that makes building simple CRUD style applications easy. If you need to extend an existing application Grails can use Hibernate to provide a mapping with your existing data.
It is based on Groovy, so while it is JVM compatible, it isn't Java.
Pick any of these:- Hibernate or iBatis
iBatis:- more control over you SQL statements.
Hibernate:- Easy to use and less to code :)