This section details frameworks that Sakai is heavily dependent on: Spring (http://www.springsource.org/), Hibernate (http://www.hibernate.org/), and numerous Apache projects (http://www.apache.org/).
Generally, Java application builders understand these frameworks. This makes it relatively easy to hire programmers with experience.
All projects are open source and the individual use does not clash with Sakai's open source license (http://www.opensource.org/licenses/ecl2.php).
Spring is tightly architected set of frameworks designed to support the main goals of building modern business applications. Spring has a broad set of abilities, from connecting to databases, to transaction, managing business logic, validation, security, ...