|By S Sangeetha||
|December 12, 2012 06:30 AM EST||
The Java Platform Enterprise Edition 7 specification early draft is available for download. All these years the focus was to introduce several APIs and technologies as part of the platform to make it more powerful, simple and complete. This is the first time the focus has shifted in a completely different direction - to bring in something new to the platform, apart from the enhancements to the existing technologies. In this article, we'll look at how Java EE evolved, became a major platform specification and understand the direction in which it is moving forward.
Java EE - Past
A brief look at the history of the Java EE - Java Platform Enterprise Edition specification reveals that every major release of the specification has been driven by a major theme.
A look at the specification details reveals that the theme for the first release of the specification J2EE 1.2 was to bring all enterprise specifications like Servlet, JSP, EJB, RMI, IIOP under one umbrella of specifications, the focus was to introduce support for distributed computing systems that reduce cost and complexity. The next release of the specification J2EE 1.3 was merely an enhancement to the J2EE 1.2 specification without any specific theme as such. Connector API, JMS Provider and Container Managed Persistence beans are prominent inclusions.
The theme for the next release, J2EE 1.4 was the support for Web Services. APIs supporting basic Web Services interoperability (like XML APIs) and support for tools for management and deployment were introduced. Even though J2EE platform addressed all the major requirements for developing, deploying and managing enterprise applications, the ‘Complexity' in programming business components and performance of the persistence tier remained the pain points of the J2EE platform.
So, Simplification and ease of development was the major focus in the next release - Java EE 5. Also the platform carried the new name- Java Platform for Enterprise Edition or Java EE in short. Annotation based programming made development lot easier and really addressed the issue of ‘Complexity'. Java EE 5 makes extensive use of annotations.
The main goal of the next release of specification Java EE 6 platform was to support all technologies and framework and still continue to simplify the platform - through three interesting features: Extensibility, Profiles and Pruning. Support for RESTful Web Services was also an important inclusion in this release.
- Extensibility - Is a mechanism which provides a way to include additional technologies and frameworks that are not part of the standard platform.
- Profiles - Are created from Java EE APIs which will have reference to Java EE platform standard specification but on top of it, will include a sub set of Java EE Platform technologies and make the platform lightweight.
- Pruning - Is an interesting concept, the Java EE technologies which are not relevant today (outdated- like JAX-RPC), whichever have been replaced by new set of technologies (like Entity Beans), technologies not supported well (like Deployment API) and technologies not widely deployed can be marked for removal from the platform.
Figure 1: History of Java EE
Java EE - Present
The next major release of Java EE platform is Java EE 7. The early draft is already made available for download and the final draft is expected to be released in Q1, 2013. The big focus of the platform is getting Java applications into cloud; make Java EE Platform suitable for Cloud environments. Emphasis of this specification is on cloud computing, emerging web technologies and continued improvements in ease of development. After a long gap, JMS API is expected to undergo a big overhaul. The Java EE platform provides services and developers are able to use services and consume them in a declarative manner. The main objective of the Java EE 7 platform is the platform itself becoming a service.
Java EE 7 has two primary focus areas:
- HTML 5
Java EE platform's container based model is well suited for Cloud environments. It is quite easy for Java EE 7 products to take the benefits of cloud environment and operate on private and public clouds and deliver their services with the help of multitenancy and elasticity. Applications deployed on the Cloud can be used by multiple tenants, however the security, isolation and QoS are guaranteed. Since container is managing the external resources like relational databases, it becomes easy for this model to be enhanced to support cloud.
The main theme would be enabling PaaS with application servers and multi-tenancy support, facilitating customers to leverage complete range of clouds - public, private and hybrid. This can be achieved by introducing new platform roles, metadata descriptor and APIs to support PaaS execution environment like multi-tenancy, resource-sharing, quality of service, elasticity and scalability. The main theme is to easily run applications on private and public clouds.
To support cloud model in the platform, most of the technologies part of this specification will get updated. Specifically, resource manager related APIs like JPA, JDBC and JMS will be updated to enable multitenancy.
Java EE 7 Platform will have first class support for some the recent developments in web space including HTML5 and Web Sockets. Plans are there to include HTTP Client API to support REST based Web Services.
Apart from Cloud and HTML 5 support, plans are there to include several new features discussed below as part of the platform.
Figure 2: Java EE 7 New Features
JCache (JSR 107)
JCache is a standardized caching API to enable scaling of enterprise applications through a caching layer accessible to all containers.
Concurrency Utilities for Java EE (JSR 236)
Extends the Concurrency API in Java SE and provides support for transaction aware and context aware APIs for asynchronous tasks.
Java API for JSON Processing (JSR 353)
A standardized Java API for parsing, generating, transforming and querying JSON. JSON is the lightweight data-interchange format popularly used in Web services for sending and receiving data particularly in RESTful Web Services. Due to non-availability of standardized Java API, different implementation libraries are used to produce/consume JSON response from Web services. The goal of this specification is to develop standardized Java API that will
- Produce and Consume JSON text in a streaming way much similar to StAX
- Build a Java Object model for JSON text using API classes much similar to DOM
However binding of JSON text to Java Objects and vice versa is also on the agenda.
Java API for WebSocket (JSR 356)
This is a standard API for creating WebSocket applications. WebSocket protocol is becoming a default standard for browsers building HTTP based applications like polling, long-polling and HTTP-streaming. This specification will provide support for WebSocket in Java EE platform for creating WebSocket for bi-directional WebSocket conversations, initiating and intercepting WebSocket events, creation and consumption of WebSocket text and binary message and working of WebSocket application within Java EE security model.
Update to Web Profile and Pruning
Java Enterprise Edition Web Profile will have JAX-RS 2.0 added to its existing set of technologies.
Some of the technologies which are outdated or not in use will be made optional as defined by the pruning process in the earlier specification (Java EE 6). Probable candidates for pruning in this release are:
- EJB Entity Beans
- JAX-RPC 1.1
- JAXR 1.0
Apart from the primary focus areas, Java EE 7 Platform has updates to the following technologies. Ease of development is the focus in all of the APIs mentioned below which have an enhancement.
- Java Persistence API (JPA)
- Multi-tenancy support
- Support for stored procedures
- Support for Schema generation
- Update and Delete Criteria queries
- Persistence Context synchronization
- Java API for RESTful Web Services (JAX-RS)
- New standardized Client API
- Support for Hypermedia
- Bean Validation API in JAX-RS for form and query parameters
- Support for Asynchronous processing
- JavaServer Faces (JSF)
- Support for HTML 5 Forms, headings and section content model and metadata
- New Components like FileUpload, BackButton etc.
- Portlet Integration
- Support for NIO.2 APIs
- Support for Async I/O
- Simplified asynchronous Servlets
- Support for Java EE Concurrency Utilities
- Support for HTML 5
- Support for Web Sockets
- Support for Cloud (PaaS model for Web applications)
- Enterprise JavaBeans (EJB)
- Support for Cloud (Support PaaS - multi-tenancy)
- Enhanced Interceptors
- Simplified programming model thru' usage of annotations
- BMP /CMP
- Web Services using JAX-RPC
- Expression Language (EL)
- Standalone JSR
- Criteria based Collection selection
- New operators
- Java Message Service (JMS - Most mature specification, undergoing a change after 10 years - April 2002)
- Support for Cloud (Multi-tenancy and other cloud features required...)
- Pluggable JMS provider
- Modest Scope
- Context and Dependency Injection (CDI)
- Life cycle events
- Injection of static variables
- Declarative package scanning
- Bean Validation
- Integration with other JSRs like JAX-RS, JAXB, JPA, CDI, EJB and JSF
- Method-level validation
- Constraint Composition
Java EE 7 Platform
Java Persistence API (JPA)
Java API for RESTful Web Services (JAX-RS)
Java ServerFaces (JSF)
Enterprise JavaBeans (EJB)
Expression Language (EL)
Java Message Service (JMS)
Context and Dependency Injection (CDI)
Table 1: Java EE 7 - Enhancements to Technologies
Java EE - Future
Support for modularity and versioning capabilities will be included in the future version. This depends on the modularity work happening on Java SE. Release of Java SE 8 will have an alignment with modularity feature in Java EE specification.
As per the latest press release a major disappointment comes on the release of the Java EE 7 specification. As per the blogspot of Linda DeMichiel- the specification lead for Java EE platform 7, the project will be delayed for another year if support for PaaS environment and multi-tenancy has to be included. So the complete support for PaaS enablement and multi-tenancy will see the light only during the next release of Java EE - Java EE 8.
Linda DeMichiel wrote on her blog - "Partially this has been due to a lack of maturity in the space for provisioning, multi-tenancy, elasticity, and the deployment of applications in the cloud. And partially it is due to our conservative approach in trying to get things "right" in view of limited industry experience in the cloud area when we started this work. Because of this, we believe that providing solid support for standardized PaaS-based programming and multi-tenancy would delay the release of Java EE 7 until the spring of 2014 - that is, two years from now and over a year behind schedule. In our opinion, that is way too long.
We have therefore proposed to the Java EE 7 Expert Group that we adjust our course of action - namely, stick to our current target release dates, and defer the remaining aspects of our agenda for PaaS enablement and multi-tenancy support to Java EE 8.".
However there are vendors like Red Hat and CloudBees who already support some parts of Java EE specifications in the Cloud environment. Experience of the vendors in this area will help in standardization of the specification better.
With the cloud support removed, Java EE 7 loses the most prominent feature, but still tries to make the release interesting with lot of additions and enhancements to existing APIs like Client APIs in JAX-RS, updated JMS API, and support for HTML 5 and updates to EL, JPA, CDI and JSF.
So the belief is Java EE 8 will provide full standardization support for cloud although the current version might not be completely ready. So "PaaS enablement and support for SaaS model" and "Modularity" will be two interesting features to look out for in the future version of the Java Platform Enterprise Edition- Java EE 8.
The contents represented in this article are purely the author's view.
The author would like to acknowledge and sincerely thank Mr. SV Subrahmanya, VP, E&R for the idea, guidance, support and constant encouragement and Mr. Piram Manickam, Senior Architect for his valuable suggestions and review.
- JCP - JSR 342: Java EE 7 (http://www.jcp.org/en/jsr/proposalDetails?id=342)
- JCP - Concurrency Utilities for Java EE (http://www.jcp.org/en/jsr/detail?id=236 )
- JCP - JCache (http://www.jcp.org/en/jsr/detail?id=236 )
- Arun Gupta's Blog (https://blogs.oracle.com/arungupta/entry/java_ee_7_key_features )
- Linda DeMichiel' s Blog (https://blogs.oracle.com/theaquarium/entry/java_ee_7_roadmap )
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