Welcome!

Java Authors: Pat Romanski, Carmen Gonzalez, Victoria Livschitz, Liz McMillan, Elizabeth White

Related Topics: Java, XML

Java: Article

How OpenKM's Technical Debt Decreased by 49% Through Code Refactoring

Initial Technical Debt of the project reduced from 84 to 42 days of remediation

Technical Debt is worth nothing if no pragmatic action is taken into code, in order to control and tackle it. To ilustrate the Scertify's capability to automatically correct code defects that increase this unintended debt, we performed code refactoring on OpenKM, an Free/Libre document management system. The initial Technical Debt of the project has been reduced by 49.2% from 84 days to 42 days. Here, at Tocea, we call it the Debt Write-Off.

For this first Debt Write-Off, we have decided to perform the refactoring of OpenKM (6.2.1-DEV).

According to Wikipedia, OpenKM is a Free/Libre document management system that provides a web interface for managing arbitrary files. OpenKM is a great tool but an audit of the code revealed some technical debt problems. That was a good opportunity to use Scertify and to be useful to an open-source community. The application consists mainly in 200K lines of code of Java. There is also Javascript, JSP, CSS... but we focus here on the Java code.

Technical debt before refactoring

Scertify Refactoring Assessment allows us to estimate the technical debt of the application. As you can see on screenshot #1, it is estimated to 84 days. This is the time needed to correct manually each error. This number only includes the time needed to make the change on the code, it does not include things like finding the file, understanding the problem, etc.

Of this 84 days, 60 represent errors that can be automatically refactored, thus taking nearly zero effort to correct.

We can take a closer look on the possibilities of automation (screenshot #2). Not all rules are currently implemented in Scertify, but we are working on it. For this project, we chose 7 rules that seemed particularly interesting.

Rules used for the refactoring

Here's a presentation of the rules used to perform the refactoring of OpenKM.

  • AvoidPrintStackTrace

    This rule reports a violation when it finds a code that catch an expression and print its stack trace to the standard error output. A logging framework should be used instead, in order to improve application's maintainability.
    The refactoring replace a call to print stack trace by a call to a logging framework. The rule can also declare the logger in the class and make the required imports. The rule can be configured to use the user's favorite framework.

    Here's the configuration used for OpenKM:

    • The logger call to use: "log.error({0}.getMessage(), {0})" {0} is replaced by the exception.
    • Do not refactor calls of printStackTrace to other IO (a file, a stream...)
    • Make logger declaration when it's needed (ie: log is not already declared in class).
    • The logger declaration to use : "private static Logger log = LoggerFactory.getLogger({0}.class);"
    • The required imports : "org.slf4j.LoggerFactory,org.slf4j.Logger"

    Original code :

    view source print? 1.catch(FileNotFoundExceptione){ e.printStackTrace(); }
  • Refactored code :

    view source print? 1.catch(FileNotFoundExceptione){ log.error(e.getMessage(),e); }
  • AddEmptyStringToConvert

    Using the concatenation of an empty string to convert a primitive type to a String is a bad practice. First of all, it makes the code less readable. It is also less efficient in most cases (the only case where the string concatenation is slightly better is when the primitive is final).

    Original code:

    view source print? 1.UserActivity.log(session.getUserID(), "DELETE_PROCESS_DEFINITION",""+processDefinitionId, null,null);

    Refactored code:

    view source print? 1.UserActivity.log(session.getUserID(), "DELETE_PROCESS_DEFINITION", String.valueOf(processDefinitionId),null,null);
  • InefficientConstructorCall

    Calling the constructor of a wrapper type, like Integer, to convert a primitive type is a bad practice. It is less efficient than calling the static method valueOf.

    Original code:

    view source print? 1.users.put(usersRead[i].getString(), newInteger(Permission.READ));

    Refactored code:

    view source print? 1.users.put(usersRead[i].getString(), newInteger(Permission.READ));
  • IfElseStmtsMustUseBraces

    This rule finds if statements that don't use braces. The refactoring adds required braces.

  • PositionLiteralsFirstInComparisonsRefactor

    This rule checks that literals are in the first position in comparisons. The following code is a violation :

    Original code:

    view source print? 1.if(action.equals("ruleList"))

    Refactored code:

    view source print? 1.if("ruleList".equals(action))

    The refactoring invert the literal and the variable. This ensures that the code cannot crash due to the variable being a null pointer.

  • MethodArgumentCouldBeFinal

    This method flags method's arguments that could be declared final and are not. The use of the final keyword is a useful information for future code readers.

  • LocalVariableCouldBeFinal

    The purpose is the same as the previous rule, except that it treats local variable and not arguments. These two rules are not critical, but since they have a huge number of violations, it is useful to get rid of them quickly with automatic refactoring.

We are now ready to perform the refactoring with Scertify.

    The refactoring process

    The refactoring process consists of two steps :

  1. Configure a xml rule repository: The first step is crucial. As we have seen in previous section, some rules need to be configured to be useful. However, it shouldn't take more than half an hour.
  2. Run Scertify to perform the refactoring: The second step is just a command line invocation, where you specify the project to refactor and the rule repository to use.

For this project of 200K lines of code, the refactoring took 2 minute. You can check the process on a smaller project in this video tutorial.

Technical debt after refactoring
Screenshot #3 is the analysis of the refactored project by Scertify Refactoring Assessment. As you can see, 24 days of technical debt have been erased.

Screenshot #4 and #5 show the difference of violations in Sonar between the original and the refactored project.

Here's the number of violations that have been corrected for each rule (*) :

  • AddEmptyStringToConvert: 232
  • AvoidPrintStackTrace: 70
  • InefficientConstructorCall: 43
  • IFElseStmtsMustUseBraces: 411
  • PositionLiteralsFirstInComparisons: 358
  • MethodArgumentCouldBeFinal: 8848
  • LocalVariableCouldBeFinal : 7622

To sum up, with Scertify we've been able to correct quickly a huge number of errors. Some of them are not critical (like MethodArgumentCouldBeFinal) but we've also been able to refactor more evolved errors like AvoidPrintStackTrace, AddEmptyStringToConvert,...

Download the source files

(*) if you do the math, you'll see that more errors have been corrected. It's due to side effects of the refactoring (correcting a rule can remove violations of other rules) and also because we manually corrected few things in the code.

Submit your project for a Debt Write-Off

If you're interested in submitting your project to the next Debt Write-off, or just give some valuable feedback... Please contact us on Twitter: @Scertify

More Stories By Michael Muller

Michael Muller, a Marketing Manager at Tocea, has 10+ years of experience as a Marketing and Communication Manager. He specializes in technology and innovative companies. He is executive editor at http://dsisionnel.com, a French IT magazine and the creator of http://d8p.it, a cool URL shortener. Dad of two kids.

@ThingsExpo Stories
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, and physical persons. In the IoT vision, every new "thing" - sensor, actuator, data source, data con...
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water, are pursuing SmartGrid initiatives that represent one of the more mature examples of SAE. We have s...
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it's a mix of architectural styles ...
The 3rd International Internet of @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 - announces that its Call for Papers is now open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series data. By focusing on enterprise applications and the data center, he will use OpenTSDB as an example t...
An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and assessments, including a decade of leading incident response and digital forensics. He is co-author of t...
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrategies, will examine why IT must finally fulfill its role in support of its SBUs or face a new round of...
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device experiences grounded in people's real needs and desires.
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...
The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. According to a recent IDG Research Services Survey this rate of traffic will only grow. What's driving t...
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective storage designed to handle the massive surge in back-end data in a world where timely analytics is e...
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using the URL as a basic building block, we open this up and get the same resilience that the web enjoys.
We are reaching the end of the beginning with WebRTC, and real systems using this technology have begun to appear. One challenge that faces every WebRTC deployment (in some form or another) is identity management. For example, if you have an existing service – possibly built on a variety of different PaaS/SaaS offerings – and you want to add real-time communications you are faced with a challenge relating to user management, authentication, authorization, and validation. Service providers will want to use their existing identities, but these will have credentials already that are (hopefully) i...
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at @ThingsExpo, Robin Raymond, Chief Architect at Hookflash, will walk through the shifting landscape of traditional telephone and voice services ...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Architect for the Internet of Things and Intelligent Systems at Red Hat, described how to revolutioniz...
Bit6 today issued a challenge to the technology community implementing Web Real Time Communication (WebRTC). To leap beyond WebRTC’s significant limitations and fully leverage its underlying value to accelerate innovation, application developers need to consider the entire communications ecosystem.
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from hardware to software, or as we like to say, it’s an Internet of many different things. The difference ...
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.