Click here to close now.

Welcome!

AJAX & REA Authors: Elizabeth White, XebiaLabs Blog, Cloud Best Practices Network, Liz McMillan, Lori MacVittie

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
Temasys has announced senior management additions to its team. Joining are David Holloway as Vice President of Commercial and Nadine Yap as Vice President of Product. Over the past 12 months Temasys has doubled in size as it adds new customers and expands the development of its Skylink platform. Skylink leads the charge to move WebRTC, traditionally seen as a desktop, browser based technology, to become a ubiquitous web communications technology on web and mobile, as well as Internet of Things...
SYS-CON Events announced today that robomq.io will exhibit at SYS-CON's @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. robomq.io is an interoperable and composable platform that connects any device to any application. It helps systems integrators and the solution providers build new and innovative products and service for industries requiring monitoring or intelligence from devices and sensors.
The WebRTC Summit 2014 New York, to be held June 9-11, 2015, at the Javits Center in New York, NY, announces that its Call for Papers is open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 16th International Cloud Expo, @ThingsExpo, Big Data Expo, and DevOps Summit.
Hosted PaaS providers have given independent developers and startups huge advantages in efficiency and reduced time-to-market over their more process-bound counterparts in enterprises. Software frameworks are now available that allow enterprise IT departments to provide these same advantages for developers in their own organization. In his workshop session at DevOps Summit, Troy Topnik, ActiveState’s Technical Product Manager, will show how on-prem or cloud-hosted Private PaaS can enable organ...
Today, IT is not just a cost center. IT is an enabler and driver of business. With the emergence of the hybrid cloud paradigm, IT now has increasingly more capabilities to create new strategic opportunities for a business. Hybrid cloud allows an organization to utilize multi-tenant public clouds, dedicated private clouds, bare metal hosting, and the associated support and services for the right use cases through an on-demand, XaaS model. This model of IT creates tremendous opportunities for busi...
DevOps tasked with driving success in the cloud need a solution to efficiently leverage multiple clouds while avoiding cloud lock-in. Flexiant today announces the commercial availability of Flexiant Concerto. With Flexiant Concerto, DevOps have cloud freedom to automate the build, deployment and operations of applications consistently across multiple clouds. Concerto is available through four disruptive pricing models aimed to deliver multi-cloud at a price point everyone can afford.
Docker is an excellent platform for organizations interested in running microservices. It offers portability and consistency between development and production environments, quick provisioning times, and a simple way to isolate services. In his session at DevOps Summit at 16th Cloud Expo, Shannon Williams, co-founder of Rancher Labs, will walk through these and other benefits of using Docker to run microservices, and provide an overview of RancherOS, a minimalist distribution of Linux designed...
Business as usual for IT is evolving into a “Make or Buy” decision on a service-by-service conversation with input from the LOBs. How does your organization move forward with cloud? In his general session at 16th Cloud Expo, Paul Maravei, Regional Sales Manager, Hybrid Cloud and Managed Services at Cisco, discusses how Cisco and its partners offer a market-leading portfolio and ecosystem of cloud infrastructure and application services that allow you to uniquely and securely combine cloud busi...
Businesses are looking to empower employees and departments to do more, go faster, and streamline their processes. For all workers – but mobile workers especially – utilizing the cloud to reconnect documents and improve processes without destructing existing workflows can have a dramatic impact on productivity. In his session at 16th Cloud Expo, Mark Grilli, vice president of Acrobat Solutions marketing at Adobe Systems Incorporated, will outline new ways that the cloud is changing the way peo...
SYS-CON Events announced today that Vitria Technology, Inc. will exhibit at SYS-CON’s @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Vitria will showcase the company’s new IoT Analytics Platform through live demonstrations at booth #330. Vitria’s IoT Analytics Platform, fully integrated and powered by an operational intelligence engine, enables customers to rapidly build and operationalize advanced analytics to deliver timely business outcomes ...
Are your applications getting in the way of your business strategy? It’s time to rethink your IT approach. In his session at 16th Cloud Expo, Madhukar Kumar, Vice President, Product Management at Liaison Technologies, will discuss a new data-centric approach to IT that allows your data, not applications, to inform business strategy. By moving away from an application-centric IT model where data integration and analysis are subservient to the constraints of applications, your organization will b...
WSM International has launched a DevOps services division that offers assessment, consulting and implementation to large enterprises and organizations with complex infrastructures. The concept of DevOps is to blend information technology (IT) software development with operations to optimize the computing infrastructure according to the specific needs of the organization. According to a recent press release from Gartner, "By 2016, DevOps will evolve from a niche strategy employed by large cloud ...
SYS-CON Events announced today that Solgenia 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, and the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Solgenia is the global market leader in Cloud Collaboration and Cloud Infrastructure software solutions. Designed to “Bridge the Gap” between Personal and Professional S...
SYS-CON Events announced today that QTS Realty Trust, one of the nation’s largest and fastest-growing providers of data center facilities and cloud services and a leader in security and compliance, 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. QTS Realty Trust, Inc. (NYSE: QTS) is a leading national provider of data center solutions and fully managed services, and a leader in security and compliance...
SYS-CON Events announced today that WSM International (WSM), the world’s leading cloud and server migration services provider, 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. WSM is a solutions integrator with a core focus on cloud and server migration, transformation and DevOps services.
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 sm...
SYS-CON Events announced today that MangoApps 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., and the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. MangoApps provides private all-in-one social intranets allowing workers to securely collaborate from anywhere in the world and from any device. Social, mobile, and eas...
Sematext is a globally distributed organization that builds innovative Cloud and On Premises solutions for performance monitoring, alerting and anomaly detection (SPM), log management and analytics (Logsene), and search analytics (SSA). We also provide Search and Big Data consulting services and offer 24/7 production support for Solr and Elasticsearch.
The speed of software changes in growing and large scale rapid-paced DevOps environments presents a challenge for continuous testing. Many organizations struggle to get this right. Practices that work for small scale continuous testing may not be sufficient as the requirements grow. In his session at DevOps Summit, Marc Hornbeek, Sr. Solutions Architect of DevOps continuous test solutions at Spirent Communications, will explain the best practices of continuous testing at high scale, which is r...
@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...