Welcome!

Java Authors: Liz McMillan, Elizabeth White, Carmen Gonzalez, Pat Romanski, Yeshim Deniz

Related Topics: Java

Java: Article

Under the Hood of a J2EE Application Server

Under the Hood of a J2EE Application Server

I recently had the opportunity to talk with many Java users about the current release and their general experiences with the platform. One of those developers told me that he didn't use J2SE but his J2EE VM sometimes caused problems.

Now most of you know that there is no such thing as a J2EE JVM. From my own experience with J2EE application servers, many do a good job hiding this from you. It can be difficult to work out which version of J2SE you are using, let alone know that J2SE is behind the scenes.

In this issue we are focusing on J2EE. If you are a core J2SE developer, there are some great tips and techniques that apply equally to J2SE and J2EE.

As a quick refresh, the J2SE platform contains the Java runtime and many of the core libraries that are used in your J2EE application. The Java runtime also contains client-side classes such as Swing. If those classes are not referenced by your application (which is normally the case), then they're not loaded at runtime. To compile Java programs use the javac compiler, which can be redistributed with the Java runtime and is also available in the Java developer kit.

One of the key technologies is the core XML library. In J2SE 5.0, the JAXP 1.3 library is bundled and includes support for XML 1.1, DOM Level 3, and SAX 2.0.2.

One new library in J2SE 5.0 that should be familiar to you is the addition of the Java Management Extension, JMX. JMX has been used in J2EE to monitor and manage J2EE applications using MBeans. The JMX framework has been extended in J2SE 5.0 with a remote interface and also has some system MBeans and a mini MBeanServer that can be used to monitor low memory conditions. This same monitoring information is published via the SNMP protocol as well.

The other side of monitoring is application profiling. The core technology here has been JVMPI, the Java profiling interface. JVMPI is still supported in J2SE 5.0 but is superseded by the new JVM TI tools interface, which provides finer-grained and less intrusive profiling. Your existing profiling tools will require updates to support the JVM TI interface, but the benefits of improved profiling will repay the investment in newer tools.

The support for network-aware distributed objects is also provided in J2SE using technologies such as RMI, JNDI, and CORBA. There have been minor increments in J2SE 5.0 for each of these technologies. One change that makes J2EE developers' coding a little easier is that RMI no longer needs a separate stub creation step.

The Java language changes, of course, apply to J2SE and J2EE and the same javac compiler is used to build both types of applications. Later releases of J2EE will be able to take advantage of features like metadata to automate many tasks, including generating deployment descriptors.

For those developers who use JavaServer Pages, the newer javac compiler will work as before. There was a proposal to increase the maximum method length due to some side effects from some of the early JSP implementations. The 64K restriction still exists but modern JSP compilers no longer run into that barrier.

Another area that is easy to overlook is database access. The JDBC framework is again delivered in J2SE. In J2SE 5.0 the addition of implementations for disconnected rowsets allows you to pass rows from your database and manipulate them without needing to maintain a live database connection. This technology even allows you to convert the database results to XML, provide updates using XML, and then resynchronize those changes at a later time.

It shouldn't be a surprise that the Java runtime is also responsible for the compilation of bytecodes and the threading framework. Many existing J2EE application servers provide support for a thread pool. In J2SE 5.0 the concurrency library also provides a choice of user space thread pools, which are portable across application servers.

J2EE application servers will also be able to provide more control over worker thread tasks by taking advantage of the new future tasks.

What does this mean for J2EE application developers? Well, regardless of the frameworks you use, J2SE 5.0 is going to bring two waves of improvements.

The first wave is updates to the libraries, such as XML, that are used by J2EE in the core platform. The second wave is to then exploit the advantages of the new features by the J2EE 5.0 platform and its components. I'm sure you'll agree that there is plenty to look forward to whether you consider yourself a J2EE developer, J2SE developer, or both.

More Stories By Calvin Austin

A section editor of JDJ since June 2004, Calvin Austin is an engineer at SpikeSource.com. He previously led the J2SE 5.0 release at Sun Microsystems and also led Sun's Java on Linux port.

Comments (1) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Most Recent Comments
noname 12/30/04 01:16:53 PM EST

With a title like Whats under the hood of a J2EE AppServer I was expecting some system-level details about J2EE AppServers...not whats new in JDK5

@ThingsExpo Stories
SYS-CON Media announced today that 9 out of 10 " most read" DevOps articles are published by @DevOpsSummit Blog. Launched in October 2014, @DevOpsSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce softw...
SYS-CON Events announced today that SafeLogic has been named “Bag Sponsor” of SYS-CON's 16th International Cloud Expo® New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. SafeLogic provides security products for applications in mobile and server/appliance environments. SafeLogic’s flagship product CryptoComply is a FIPS 140-2 validated cryptographic engine designed to secure data on servers, workstations, appliances, mobile devices, and in the Cloud.
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal an...
15th Cloud Expo, which took place Nov. 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA, expanded the conference content of @ThingsExpo, Big Data Expo, and DevOps Summit to include two developer events. IBM held a Bluemix Developer Playground on November 5 and ElasticBox held a Hackathon on November 6. Both events took place on the expo floor. The Bluemix Developer Playground, for developers of all levels, highlighted the ease of use of Bluemix, its services and functionality and provide short-term introductory projects that developers can complete between sessions.
SYS-CON Events announced today that Akana, formerly SOA Software, has been named “Bronze Sponsor” of SYS-CON's 16th International Cloud Expo® New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. Akana’s comprehensive suite of API Management, API Security, Integrated SOA Governance, and Cloud Integration solutions helps businesses accelerate digital transformation by securely extending their reach across multiple channels – mobile, cloud and Internet of Things. Akana enables enterprises to share data as APIs, connect and integrate applications, drive part...
Since 2008 and for the first time in history, more than half of humans live in urban areas, urging cities to become “smart.” Today, cities can leverage the wide availability of smartphones combined with new technologies such as Beacons or NFC to connect their urban furniture and environment to create citizen-first services that improve transportation, way-finding and information delivery. In her session at @ThingsExpo, Laetitia Gazel-Anthoine, CEO of Connecthings, will focus on successful use cases.
SYS-CON Events announced today that Vicom Computer Services, Inc., a provider of technology and service solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. They are located at booth #427. Vicom Computer Services, Inc. is a progressive leader in the technology industry for over 30 years. Headquartered in the NY Metropolitan area. Vicom provides products and services based on today’s requirements around Unified Networks, Cloud Computing strategies, Virtualization around Software defined Data Ce...
SYS-CON Events announced today that Open Data Centers (ODC), a carrier-neutral colocation provider, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. Open Data Centers is a carrier-neutral data center operator in New Jersey and New York City offering alternative connectivity options for carriers, service providers and enterprise customers.
SYS-CON Events announced today that Dyn, the worldwide leader in Internet Performance, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Dyn is a cloud-based Internet Performance company. Dyn helps companies monitor, control, and optimize online infrastructure for an exceptional end-user experience. Through a world-class network and unrivaled, objective intelligence into Internet conditions, Dyn ensures traffic gets delivered faster, safer, and more reliably than ever.
The 3rd International @ThingsExpo, co-located with the 16th International Cloud Expo – to be held June 9-11, 2015, at the Javits Center in New York City, NY – is now accepting Hackathon proposals. Hackathon sponsorship benefits include general brand exposure and increasing engagement with the developer ecosystem. At Cloud Expo 2014 Silicon Valley, IBM held the Bluemix Developer Playground on November 5 and ElasticBox held the DevOps Hackathon on November 6. Both events took place on the expo floor. The Bluemix Developer Playground, for developers of all levels, highlighted the ease of use of...
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps, abiding by privacy concerns and making the concept a reality. These challenges can't be addressed w...
SYS-CON Events announced today that AIC, a leading provider of OEM/ODM server and storage solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. AIC is a leading provider of both standard OTS, off-the-shelf, and OEM/ODM server and storage solutions. With expert in-house design capabilities, validation, manufacturing and production, AIC's broad selection of products are highly flexible and are configurable to any form factor or custom configuration. AIC leads the industry with nearly 20 years of ...
DevOps Summit 2015 New York, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.
SYS-CON Events announced today that Liaison Technologies, a leading provider of data management and integration cloud services and solutions, has been named "Silver Sponsor" of SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York, NY. Liaison Technologies is a recognized market leader in providing cloud-enabled data integration and data management solutions to break down complex information barriers, enabling enterprises to make smarter decisions, faster.
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal today!
@ThingsExpo has been named the Top 5 Most Influential M2M Brand by Onalytica in the ‘Machine to Machine: Top 100 Influencers and Brands.' Onalytica analyzed the online debate on M2M by looking at over 85,000 tweets to provide the most influential individuals and brands that drive the discussion. According to Onalytica the "analysis showed a very engaged community with a lot of interactive tweets. The M2M discussion seems to be more fragmented and driven by some of the major brands present in the M2M space. This really allows some room for influential individuals to create more high value inter...
@ThingsExpo has been named the Top 5 Most Influential Internet of Things Brand by Onalytica in the ‘The Internet of Things Landscape 2015: Top 100 Individuals and Brands.' Onalytica analyzed Twitter conversations around the #IoT debate to uncover the most influential brands and individuals driving the conversation. Onalytica captured data from 56,224 users. The PageRank based methodology they use to extract influencers on a particular topic (tweets mentioning #InternetofThings or #IoT in this case) takes into account the number and quality of contextual references that a user receives.
17th Cloud Expo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterprises are using some form of XaaS – software, platform, and infrastructure as a service.
Enterprise IoT is an exciting and chaotic space with a lot of potential to transform how the enterprise resources are managed. In his session at @ThingsExpo, Hari Srinivasan, Sr Product Manager at Cisco, will describe the challenges in enabling mass adoption of IoT, and share perspectives and insights on architectures/standards/protocols that are necessary to build a healthy ecosystem and lay the foundation to for a wide variety of exciting IoT use cases in the years to come.
Avnet, Inc. has announced that it ranked No. 4 on the InformationWeek Elite 100 – a list of the top business technology innovators in the U.S. Avnet was recognized for the development of an innovative cloud-based training system that serves as the foundation for Avnet Academy – the company’s education and training organization focused on technical training around top IT vendor technologies. The development of this system allowed Avnet to quickly expand its IT-related training capabilities around the world, while creating a new service that Avnet and its IT solution providers can offer to their...