Welcome!

AJAX & REA Authors: Elizabeth White, Trevor Parsons, ChandraShekar Dattatreya, Liz McMillan, David H Deans

Related Topics: Java, AJAX & REA

Java: Article

Behind the Scenes of Serialization in Java

The right serialization strategy is central for achieving performance and scalability

When building distributed applications one of the central performance-critical components is serialization. Most modern frameworks make it very easy to send data over the wire. In many cases you don’t see at all what is going on behind the scenes. Choosing the right serialization strategy however is central for achieving good performance and scalability. Serialization problems affect CPU, memory, network load and response times.

Java provides us with a large variety of serialization technologies. The actual amount of data which is sent over the wire can vary substantially. We will use a very simple sample where we send the firstname, lastname and birthdate over the wire. Then we’ll see how big the actual payload gets.

Binary Data
As a reference we start by sending only the payload. This is the most efficient way of sending data, as there is no overhead involved. The downside is that due to the missing metadata the message can only be de-serialized if we know the exact serialization method. This approach also has a very high testing and maintenance effort and we have to handle all implementation complexity ourselves. The figure below shows what our payload looks like in binary format.

Binary Representation of Address Entity

Binary Representation of Address Entity

Java Serialization
Now we switch to standard serialization in Java. As you can see in below we are now transferring much more metadata. This data is required by the Java Runtime to rebuild the transferred object at the receiver side. Besides structural information the metadata also contains versioning information which allows communication across different versions of the same object. In reality, this feature often turns out to be harder than it initially looks. The metadata overhead in our example is rather high. This is caused by large amount of data in the GregorianCalendar Object we are using. The conclusion that Java Serialization comes with a very high overhead per se, however is not valid. Most of this metadata will be cached for subsequent invocations.

 

Person Entity with Java Serialization

Person Entity with Java Serialization
Java also provides the ability to override the Serialization behavior using the Externalizable interface. This enables us to implement a more efficient serialization strategy. In our example we could only serialize the birthdate as a long rather than a full object. The downside again is the increased effort regarding testing an maintainability

Java Serialization is by default used in RMI communication when not using IIOP as a protocol. Application server providers also offer their own serialization stacks which are more efficient than default serialization. If interoperability is not important, provider-specific implementations are the better choice.

Alternatives
The Java ecosystem also provides interesting alternatives to Java Serialization. A widely known one is Hessian which can be easily used with Spring. Hessian allows an easy straightforward implementation of services. Underneath it uses a binary protocol. The figure below shows our data serialized with Hessian. As you can see the transferred data is very slim. Hessian therefore provides an interesting alternative to RMI.

Hessian Binary Representation of Person Object

Hessian Binary Representation of Person Object

JSON
A newcomer in serialization formats is JSON (JavaScript Object Notation). Originally used as a text-based format for representing JavaScript objects, it’s been more and more adopted in other languages as well. One reason is the rise of Ajax applications, but also the availability of frameworks for most programming languages.

As JSON is a purely text-based representation it comes with a higher overhead than the previously shown serialization approaches. The advantage is that it is more lightweight than XML and it has good support for describing metadata. The Listing below shows our person object represented in JSON.

{"firstName":"Franz",
"lastName":"Musterman",
"birthDate":"1979-08-13"
}

XML
XML for sure is the standard format for exchanging data in heterogeneous systems. One nice feature of XML is the out-of-the-box support for data validation, which is especially important in integration scenarios. The amount of metadata, however, can become really high – depending on the used mapping. All data is transferred in text format by default. However the usage of CDATA tags enables us to send binary data. The listing below shows our person object in XML. As you can see the metadata overhead is quite high.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<person>
  <birthDate>1979-08-13T00:00:00-07:00</birthDate>
  <firstName>Franz</firstName>
  <lastName>Musterman</lastName>
</person>

Fast InfoSet
Fast InfoSet
is becoming a very interesting alternative to XML. It is more or less a lightweight version of XML, which reduces unnecessary overhead and redundancies in data. This leads to smaller data set and better serialization and deserialization performance.

When working with JAX-WS 2.0 you can enable Fast InfoSet serialization by using the @FastInfoset annotation. Web Service stacks then automatically detect whether it can be used for cross service communication using HTTP Accept headers.

When looking at data serialized using Fast InfoSet the main difference you will notice is that there are no end tags. After their first occurrence there are only referenced by an index. There are a number of other indexes for content, namespaces etc.

Data is prefixed with its length. This allows faster and more efficient parsing. Additionally binary data can avoid being serialized in base64 encoding as in an XML.

In tests with standard documents the transfer size could be shrunk down to only 20 percent of the original size and the serialization speed could be doubled. The listing below shows our person object now serialized with Fast InfoSet. For Illustration purposes I skipped the processing instructions and I used a textual representation instead of binary values. Values in curly braces refer to indexed values. Values in brackets refer to the use of an index.

{0}<person>
{1}<birthDate>{0}1979-08-13T00:00:00-07:00
{2}<firstName>{1}Franz
{3}<lastName>{2}Musterman

The real advantage however can be seen when we look what the next address object would look like. As the listing below shows we can work mostly with index data only.

[0]<>
[1]<>{0}
[2]<>{3}Hans
[3}<>{4}Musterhaus

Object Graphs
Object graphs can get quite tricky to serialize. This form of serialization is not supported by all protocols. As we need to work with reference to entities, the language used by the serialization approach must provide a proper language construct. While this is no problem in serialization formats which are used for (binary) RPC-style interactions, it is often not supported out-of-the-box by text-based protocols. XML itself, for example, supports serializing object graphs using references. The WS-I however forbids the usage of the required language construct.

If a serialization strategy does not support this feature it can lead to performance and functional problems, as entities get serialized individually for each occurrence of a reference. If we are, for example, serializing addresses which have reference to country information, this information will then be serialized for each and every address object leading to large serialization sizes.

Conclusion
Today there are numerous variants to serialize data in Java. While binary serialization keeps being the most efficient approach, modern text-based formats like JSON or Fast Infoset provide valid alternatives – especially when interoperability is a primary concern. Modern frameworks often allow using multiple serialization strategies at the same time. So the approach can even be selected dynamically at runtime.

Related reading:

  1. Behind the scenes of ASP.NET MVC 2 – Understand the internals to build better apps With Visual Studio 2010, Microsoft is shipping the next version...
  2. 52 weeks of Application Performance – The dynaTrace Almanac 2010 is over and there has been a log going...
  3. 7 Rules to Improve your Application Performance Practices In this post I discuss the seven most important steps...
  4. Is There a Business Case for Application Performance? We all know that slow performance – and service disruption...
  5. Applying Maslow’s Pyramid to Application Performance This time I take an a bit unconventional approach towards...

More Stories By Alois Reitbauer

Alois Reitbauer works as a Technology Strategist for dynaTrace Software where he is leading the Methods and Technology team. As part of the R&D team he influences the dynaTrace product strategy and works closely with key customers in implementing performance management solution for the entire lifecylce. Alois has 10 years experience as architect and developer in the Java and .NET space. He is a frequent speaker at technology conferences on performance and architecture related topics and regularly publishes articles blogs on blog.dynatrace.com

@CloudExpo Stories
SYS-CON Events announced today Isomorphic Software, the global leader in high-end, web-based business applications, will exhibit at SYS-CON's DevOps Summit 2015 New York, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Isomorphic Software is the global leader in high-end, web-based business applications. We develop, market, and support the SmartClient & Smart GWT HTML5/Ajax platform, combining the productivity and performance of traditional desktop software ...
The BPM world is going through some evolution or changes where traditional business process management solutions really have nowhere to go in terms of development of the road map. In this demo at 15th Cloud Expo, Kyle Hansen, Director of Professional Services at AgilePoint, shows AgilePoint’s unique approach to dealing with this market circumstance by developing a rapid application composition or development framework.
“We help people build clusters, in the classical sense of the cluster. We help people put a full stack on top of every single one of those machines. We do the full bare metal install," explained Greg Bruno, Vice President of Engineering and co-founder of StackIQ, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
AppZero has announced that its award-winning application migration software is now fully qualified within the Microsoft Azure Certified program. AppZero has undergone extensive technical evaluation with Microsoft Corp., earning its designation as Microsoft Azure Certified. As a result of AppZero's work with Microsoft, customers are able to easily find, purchase and deploy AppZero from the Azure Marketplace. With just a few clicks, users have an Azure-based solution for moving applications to the...
The cloud is becoming the de-facto way for enterprises to leverage common infrastructure while innovating and one of the biggest obstacles facing public cloud computing is security. In his session at 15th Cloud Expo, Jeff Aliber, a global marketing executive at Verizon, discussed how the best place for web security is in the cloud. Benefits include: Functions as the first layer of defense Easy operation –CNAME change Implement an integrated solution Best architecture for addressing network-l...
“In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com...
"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The move in recent years to cloud computing services and architectures has added significant pace to the application development and deployment environment. When enterprise IT can spin up large computing instances in just minutes, developers can also design and deploy in small time frames that were unimaginable a few years ago. The consequent move toward lean, agile, and fast development leads to the need for the development and operations sides to work very closely together. Thus, DevOps become...
"Our premise is Docker is not enough. That's not a bad thing - we actually love Docker. At ActiveState all our products are based on open source technology and Docker is an up-and-coming piece of open source technology," explained Bart Copeland, President & CEO of ActiveState Software, in this SYS-CON.tv interview at DevOps Summit at Cloud Expo®, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Verizon Enterprise Solutions is simplifying the cloud-purchasing experience for its clients, with the launch of Verizon Cloud Marketplace, a key foundational component of the company's robust ecosystem of enterprise-class technologies. The online storefront will initially feature pre-built cloud-based services from AppDynamics, Hitachi Data Systems, Juniper Networks, PfSense and Tervela. Available globally to enterprises using Verizon Cloud, Verizon Cloud Marketplace provides a one-stop shop fo...
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, 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. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, p...
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover ...

ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ --  IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's

SYS-CON Events announced today that IDenticard 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. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada...
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 conf...
Leysin American School is an exclusive, private boarding school located in Leysin, Switzerland. Leysin selected an OpenStack-powered, private cloud as a service to manage multiple applications and provide development environments for students across the institution. Seeking to meet rigid data sovereignty and data integrity requirements while offering flexible, on-demand cloud resources to users, Leysin identified OpenStack as the clear choice to round out the school's cloud strategy. Additional...
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...
“DevOps is really about the business. The business is under pressure today, competitively in the marketplace to respond to the expectations of the customer. The business is driving IT and the problem is that IT isn't responding fast enough," explained Mark Levy, Senior Product Marketing Manager at Serena Software, in this SYS-CON.tv interview at DevOps Summit, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Mobile commerce traffic is surpassing desktop, yet less than 20% of sales in the U.S. are mobile commerce sales. In his session at 15th Cloud Expo, Dan Franklin, Segment Manager, Commerce, at Verizon Digital Media Services, defined mobile devices and discussed how next generation means simplification. It means taking your digital content and turning it into instantly gratifying experiences.