Welcome!

Java IoT Authors: Liz McMillan, Carmen Gonzalez, Yeshim Deniz, Scott Allen, Elizabeth White

Related Topics: Java IoT, Open Source Cloud

Java IoT: Article

A Light Java Runtime to Bundle with Applications

Steve Jobs once said that Java is a big heavyweight ball and chain. Good news: the ball is now optional!

Java Development on Ulitzer

Steve Jobs once said that Java is a big heavyweight ball and chain. Good news: the ball is now optional! In this article, I share results we achieved after implementing a component deployment model, also known as JRE modularity, for the core of J2SE 5.0 and Java SE 6. The technology’s been in production use for more than two years and proved effective.

This is not a mere “Java gets smaller” message. Given that Project Jigsaw is emerging in JDK 7, I also offer some insights on the challenges that any implementation of modularity for the Java SE core may face, all derived from our practical experience.

“Divide and Conquer” Has Worked Out
We did not pioneer the idea that the monolithic Java SE platform needs to be split into components, it was in the air. We merely found a way of how to do that without breaking Java compatibility and implemented it in a compliant Java SE VM, Excelsior JET, back in 2007.

The goal was to let Java programmers bundle a light version of the Java Runtime with their applications leaving the unused components out so as to reduce the size of the installation package. Easier said than done, but we’ve got it made in a Java spec-compliant manner and called the technology Java Runtime Slim-Down (after Project Jigsaw appeared, it’s finally got to me that we should have to call it “Project Rock breaker” or the like).

It has been proved effective for many Java applications. For GUI applications, in particular, the size of a complete installation package with bundled Java Runtime starts from 5MB. In support of this assertion, I refer you to SWTPaint, a sample program taken from the latest Eclipse SDK.

The use of Java Runtime Slim-Down yields results you won’t get with any other Java deployment tool:

  • The size of the SWTPaint installer is 5.5MB (here is a direct download link).
  • The installed application need not the JRE to run and does not download any components from the Internet (so it won’t disturb your firewall).

Note that the GUI application in question is written in Java and uses Java SE 6. Oh, sorry! I had to mention that download size for Swing applications start from 8MB. Stirring the flame of Swing vs. SWT was by no means my intention. We prepared installation packages for a few sample applications, both Swing- and SWT-based, and you may download them from this page. If you are still in doubt, try the deployment technique yourself. This flash demo will help you get started.

There are good reasons for end users to love “all-inclusive” installation packages at reduced footprint rates, and it’s where a lightweight Java Runtime is of much help. At a larger scale, however, the lack of the JRE modularity impeded the evolution and adoption of the Java SE platform.

In Between a Rock and a Hard Place
A bit of history. Remember JSR-83, a proposal on the “multiarray” package originated by IBM. Its implementation could have had a great impact on the number crunching performance in Java. Nevertheless, it was approved only as a Java Standard Extension, never appeared among the core packages and eventually was withdrawn. In the final ballot, Sun made a noticeable comment: “...The proposal requires at least 82 new classes, and this seems inappropriate for the J2SE core...”. Though I personally was disappointed with the outcome, the need to damp the Java core inflation down sounded reasonable

Other JSRs were more lucky and the Java Community Process kept Java SE moving forward over the years. In 2006, I attended the Java Licensee Day event. During the Q&A part of the session devoted to then new Java SE 6, one of the licensees sharply asked: “With each release the JRE gets bigger and bigger. Our customers do not need all those new APIs. When will it stop bloating?” I then found myself thinking I agreed with him but I would rather say “Not all our customers need all those new APIs...”.

The question is how many “useful” APIs have not been approved just not to make the JRE bigger? One may ask also how many “useless” APIs have been approved and did make the JRE bigger? It’s clear that requirements of different projects vary and there is no single answer to these questions, but splitting the JRE into components could resolve these issues gracefully.

Here’s a practical example from our support records. We have customers who previously got stuck with J2SE 1.4.2 simply because the footprint of later Java versions was unacceptable for their deployment requirements. Now, after switching to the component model, they are happy users of Java SE 6.

However, I would not like to discuss the Sun’s policy on modularizing Java SE here. There were many pros and cons to consider, both technical an legal, and I fully realized some of them only when working on the Java Runtime Slim-Down technology. No shooting (in the foot)

As often happens, once we had started the design, the scope of work suddenly increased. For the truth to be told, we would not reach the goal by simply splitting the Java SE API into components and enabling the user to drop some of them. The big question was how to make the technology usable and reliable? After all, we did not want to create a thing that does not work just because the programmer removed some components too aggressively. We decided to explore the limits of this approach by interviewing those enthusiasts who pursued us for this matter. The results confirmed our suspicion – programmers are not always aware of what parts of the Java SE API are actually used in their applications. A good illustration would be the following transcript written then:

Client: I do not use that “Baggage-To-Trim” API and no longer want to carry it with my app. As you are a JVM vendor, make me happy, please.

Support Engineer: We understand you concern. Are you sure you don’t use the “Baggage-To-Trim” API?

Client: Absolutely.

Support Engineer:. We kindly ask you to double check it. Please run your app with java –verbose:class and inspect the log.

Client: Oops.. You surprised me! It’s proved to be used. Frankly speaking, I did not write that code where it’s used. Let me think of it.

Needless to say that we also had to think of it. In addition, Java SE components may depend on each other implicitly, via the implementing classes, and most programmers not familiar with the internals could not play safe when removing the components.

We conducted some R&D and figured out that such a technology should come with tools that help the user not shoot himself in the foot and rules which, just in case, provide the fastest recovery.

Tools and Rules
The final solution included a dependency analyzer and “safety net”. The analyzer takes the application’s classes, infers what Java SE components are likely in use and advises to the user.

Under the covers, it’s not simply checking import dependencies as that would work poorly in terms of precision. For instance, such a simplistic analysis would not have revealed that the SWT-AWT bridge, which is part of the SWT package, is not used by the SWTPaint application mentioned above. As a result, the AWT component would be sucked in and the installation size would increase. That said, analyzer design and testing had engaged us for some time.

Does it guarantee that any deployed application will never miss the removed components? I would not bet money on it. After all, a programmer could detach some components by mistake or an application may load a plug-in that uses the Java SE API more extensively than the application itself. Here the following rule comes into play. All removed components are put into a detached package and the developer has to place it on a Web server at the URL s/he assigned when creating the installation. The Web server is considered a "safety net": should the deployed application attempt to use any of the removed components, the Java Runtime will pull the package down from the server and load the requested Java classes.

On the formal side of things, we run the Java Compatibility Kit (JCK) deployed in this mode with some and all Java SE components detached. Noteworthy is that all the tests pass.

However, it is unlikely that a download of a detached package will occur in practice, provided the developer listened to the word of wisdom from the analyzer. For example, these sample applications have been downloaded over a thousand of times since we published them in May 2007, but there was not a single download of a detached package so far.

The last note is about the splitting. We have managed to carve a kernel part of Java SE, about 4MB, that have to be bundled with any application. We could not get it smaller. We wanted to break down the whole thing into more components, each of a smaller size, but were unable to do that. In general, we could obtain better download size figures if the Java SE API implementation classes would not be so tightly coupled, full of cross-references, strongly connected, melted and fused together.

The Truth About Sun Java Kernel
Initially, Sun Java Kernel was supposed include a deployment technology for reducing the download size. But what appeared in Java 6 Update 10 under the name Java Kernel is still far from the solution. The Java Kernel contains the VM and some core classes like java.lang.*, java.io.* and meets the needs of HelloWorld of sorts only. Upon application launch, the Java Kernel inevitably starts downloading the remaining packages from a Sun web site and no means are provided to package the required bundles with the application. In essence, the end users "download a downloader" and all you can do with it is specify which missing bundles must be downloaded first. This short table highlights the key differences between Java Runtime Slim-Down and Java Kernel:

You may find more details in the Java Kernel FAQ. Probably, the Java Kernel is just a preliminary step toward a solution that may appear in the future.

Historical Notes
The first mention of the JRE modularity being found in the Annals relates to the times of JDK 1.2(!) The discussions lasted for years, the first implementation in the Sun JRE was planned for Java 1.5, then moved to Java 6. The Java Kernel appeared in Java 6 Update 10 proved to be far from the solution.

In parallel with the Java Kernel, Java Module System (JSR-277) was in the works, which, in particular, could address the JRE modularity problem but the deadlock between Sun and an OSGi lobby had it buried.

Finally, in the end of 2008, Project Jigsaw was announced and “Episode IV. The New Hope” commenced.

Four Challenges for Jigsaw
I’m not with the Java SE core group at Sun but I’ve been working with the Java SE core for more than ten years. Below I share my opinion on the main challenges to the adoption of Jigsaw in the future.

World Peace
The corporate battle around OSGi needs a break. None has won and the Java Community has lost because, time after time, JRE modularity solutions appear to disappear. To use or not to use OSGi now is less of an issue as compared with the next challenge.

Backward Compatibility
In modular approach, each component should be sufficiently isolated and import relations should be declared statically. Besides that, import graph should be (close to) acyclic to minimize the number of indirectly used components.

The problem is that the reference implementation of the Java SE API was coded without having modularity in mind. Somewhat it was a side-effect of the Java’s lazy classloading which created an illusion that a use of any class in Java code costs nothing until it’s actually executed at run time. It’s proved to be a technical debt and now is the time to pay the interest.

In practice, it means that spaghetti-like dependencies between the implementing classes are omnipresent and breaking the ties without breaking backward compatibility with previous Java versions is double tough. The danger is to create something like Apache Harmony: everything is implemented with an elegant internal architecture, samples work, but existing Java apps have issues.

Profiles All Over Again?
Some outlines of Jigsaw mention so called Java SE Profiles, e.g. Profile for headless apps, for basic RIA, for rich desktop apps, etc. A potential threat here is the repetition of the same old story of the monolithic JRE unless user-defined profiles will be allowed. One size does not fit all even if the presets are defined carefully.

Need for Total Modularization
There is a risk to getting no benefits from the JRE modularity alone. Most real-world applications use third-party components (Java APIs), which are yet to be modularized. Typically, applications tend to use only a part of the functionality provided by an API. Without total modularization, chances are good that unnecessary parts of (modularized) JRE will be taken in due to use of a (monolithic) third-party component. And it’s no matter whether the import declarations will be written in OSGi bundle manifests or somewhere else.

Conclusion
In closing, I’d like to say that we implemented Java Runtime Slim-Down due to high demand from our clients. I strongly believe, however, that modularized JRE has to come with Java SE out-of-the-box, not just as a vendor solution. I wrote this article with a little hope that our past experience would be of some help for the future development of the Java platform.

P.S. One man said that Java is a big heavyweight ball and chain. Good news: the ball is now optional! You may detach it and use module Chain only.

More Stories By Vitaly Mikheev

Vitaly Mikheev is the chief technology officer for Excelsior, LLC, a company focusing on design and development of optimizing compilers. Vitaly has been involved in software development since 1987 and focused on compiler construction technologies for the last decade. He started working with Java in 1998 as the architect of the Excelsior Java Virtual Machine. Before that, he worked on proprietary optimizing compilers for Nortel Networks. Vitaly is a member of ACM and a co-author of the patent on the garbage collector algorithm implemented in the Samsung's J2ME CDC virtual machine. He holds an MS in computer science from the Novosibirsk State University, Russia.

Comments (0)

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.


@ThingsExpo Stories
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settle...
In his session at @ThingsExpo, Steve Wilkes, CTO and founder of Striim, will delve into four enterprise-scale, business-critical case studies where streaming analytics serves as the key to enabling real-time data integration and right-time insights in hybrid cloud, IoT, and fog computing environments. As part of this discussion, he will also present a demo based on its partnership with Fujitsu, highlighting their technologies in a healthcare IoT use-case. The demo showcases the tracking of patie...
The explosion of new web/cloud/IoT-based applications and the data they generate are transforming our world right before our eyes. In this rush to adopt these new technologies, organizations are often ignoring fundamental questions concerning who owns the data and failing to ask for permission to conduct invasive surveillance of their customers. Organizations that are not transparent about how their systems gather data telemetry without offering shared data ownership risk product rejection, regu...
The best way to leverage your Cloud Expo presence as a sponsor and exhibitor is to plan your news announcements around our events. The press covering Cloud Expo and @ThingsExpo will have access to these releases and will amplify your news announcements. More than two dozen Cloud companies either set deals at our shows or have announced their mergers and acquisitions at Cloud Expo. Product announcements during our show provide your company with the most reach through our targeted audiences.
SYS-CON Events announced today that Cloud Academy will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud computing technologies. Ge...
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, 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.
Bert Loomis was a visionary. This general session will highlight how Bert Loomis and people like him inspire us to build great things with small inventions. In their general session at 19th Cloud Expo, Harold Hannon, Architect at IBM Bluemix, and Michael O'Neill, Strategic Business Development at Nvidia, discussed the accelerating pace of AI development and how IBM Cloud and NVIDIA are partnering to bring AI capabilities to "every day," on-demand. They also reviewed two "free infrastructure" pr...
Have you ever noticed how some IT people seem to lead successful, rewarding, and satisfying lives and careers, while others struggle? IT author and speaker Don Crawley uncovered the five principles that successful IT people use to build satisfying lives and careers and he shares them in this fast-paced, thought-provoking webinar. You'll learn the importance of striking a balance with technical skills and people skills, challenge your pre-existing ideas about IT customer service, and gain new in...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develop...
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
While not quite mainstream yet, WebRTC is starting to gain ground with Carriers, Enterprises and Independent Software Vendors (ISV’s) alike. WebRTC makes it easy for developers to add audio and video communications into their applications by using Web browsers as their platform. But like any market, every customer engagement has unique requirements, as well as constraints. And of course, one size does not fit all. In her session at WebRTC Summit, Dr. Natasha Tamaskar, Vice President, Head of C...
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you...
SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 20th International Cloud Expo, which will take place on June 6–8, 2017, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buyers...
In the enterprise today, connected IoT devices are everywhere – both inside and outside corporate environments. The need to identify, manage, control and secure a quickly growing web of connections and outside devices is making the already challenging task of security even more important, and onerous. In his session at @ThingsExpo, Rich Boyer, CISO and Chief Architect for Security at NTT i3, will discuss new ways of thinking and the approaches needed to address the emerging challenges of securit...
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions with...
It is one thing to build single industrial IoT applications, but what will it take to build the Smart Cities and truly society changing applications of the future? The technology won’t be the problem, it will be the number of parties that need to work together and be aligned in their motivation to succeed. In his Day 2 Keynote at @ThingsExpo, Henrik Kenani Dahlgren, Portfolio Marketing Manager at Ericsson, discussed how to plan to cooperate, partner, and form lasting all-star teams to change the...
“We're a global managed hosting provider. Our core customer set is a U.S.-based customer that is looking to go global,” explained Adam Rogers, Managing Director at ANEXIA, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.