Jakarta EE, formerly Java Platform, Enterprise Edition (Java EE) and Java 2 Platform, Enterprise Edition (J2EE), is a set of specifications, extending Java SE with specifications for enterprise features such as distributed computing and web services. Jakarta EE applications are run on reference runtimes, which can be microservices or application servers, which handle transactions, security, scalability, concurrency and management of the components they are deploying. Jakarta EE is defined by its specification. The specification defines APIs (application programming interface) and their interactions. As with other Java Community Process specifications, providers must meet certain conformance requirements in order to declare their products as Jakarta EE compliant. Examples of contexts in which Jakarta EE referencing runtimes are used are: e-commerce, accounting, banking information systems.

History

The platform was known as Java 2 Platform, Enterprise Edition or J2EE from version 1.2, until the name was changed to Java Platform, Enterprise Edition or Java EE in version 1.5. Java EE was maintained by Oracle under the Java Community Process. On September 12, 2017, Oracle Corporation announced that it would submit Java EE to the Eclipse Foundation. The Eclipse top-level project has been named Eclipse Enterprise for Java (EE4J). The Eclipse Foundation could not agree with Oracle over the use of javax and Java trademarks. Oracle owns the trademark for the name "Java" and the platform was renamed from Java EE to Jakarta EE. The name refers to the largest city on the island of Java and also the capital of Indonesia, Jakarta. The name should not be confused with the former Jakarta Project which fostered a number of current and former Java projects at the Apache Software Foundation.

Specifications

Jakarta EE includes several specifications that serve different purposes, like generating web pages, reading and writing from a database in a transactional way, managing distributed queues. The Jakarta EE APIs include several technologies that extend the functionality of the base Java SE APIs, such as Jakarta Enterprise Beans, connectors, servlets, Jakarta Server Pages and several web service technologies.

Web specifications

Web service specifications

Enterprise specifications

Other specifications

Web profile

In an attempt to limit the footprint of web containers, both in physical and in conceptual terms, the web profile was created, a subset of the Jakarta EE specifications. The Jakarta EE web profile comprises the following:

Certified referencing runtimes

Although by definition all Jakarta EE implementations provide the same base level of technologies (namely, the Jakarta EE spec and the associated APIs), they can differ considerably with respect to extra features (like connectors, clustering, fault tolerance, high availability, security, etc.), installed size, memory footprint, startup time, etc.

Jakarta EE

Java EE

Code sample

The code sample shown below demonstrates how various technologies in Java EE 7 are used together to build a web form for editing a user. In Jakarta EE a (web) UI can be built using Jakarta Servlet, Jakarta Server Pages (JSP), or Jakarta Faces (JSF) with Facelets. The example below uses Faces and Facelets. Not explicitly shown is that the input components use the Jakarta EE Bean Validation API under the covers to validate constraints.

Example Backing Bean class

To assist the view, Jakarta EE uses a concept called a "Backing Bean". The example below uses Contexts and Dependency Injection (CDI) and Jakarta Enterprise Beans (EJB).

Example Data Access Object class

To implement business logic, Jakarta Enterprise Beans (EJB) is the dedicated technology in Jakarta EE. For the actual persistence, JDBC or Jakarta Persistence (JPA) can be used. The example below uses EJB and JPA. Not explicitly shown is that JTA is used under the covers by EJB to control transactional behavior.

Example Entity class

For defining entity/model classes Jakarta EE provides the Jakarta Persistence (JPA), and for expressing constraints on those entities it provides the Bean Validation API. The example below uses both these technologies.