Welcome!

Java IoT Authors: Dana Gardner, Automic Blog, Pat Romanski, Liz McMillan, Shelly Palmer

Related Topics: Java IoT

Java IoT: Article

Detecting J2EE Problems Before They Happen

A runtime abstract application model derived automatically from app server using stored knowledge of Java EE construction

This article introduces a new form of analysis for Java EE applications: a runtime abstract application model derived automatically from an application server using stored knowledge of Java EE construction. The model is used dynamically to do extensive automatic checks for a range of construction errors that could produce poor performance or unreliability. The model also lets server behavior be dynamically visualized in real-time or retrospectively.

There has been a lot of attention given lately to the topic of of Model Driven Architecture (MDA), which aims to create working systems by generating source code from successively transformed high-level component models. While doubts have been cast on the real-world robustness of this idea - and previous code-generation solutions haven't been a big success - there's no doubt that the possibility of working with software at a more abstract level holds a strong appeal for engineers.

Although the inauspicious history of CASE tools suggests that making a project dependent on model-driven code generation could be limiting, the central tenet of MDA - the ability to view and analyze our application at an abstract level - is a powerful and attractive goal. Even if our application grew beyond an initial set of predefined patterns and code templates we'd still like to be able to validate and understand it based on a design-level description of its operation.

Derived Model Analysis (DMA)
If we don't have a predefined model, how are we going to get one? Well, if you try to describe your application to someone else you'll almost certainly use architecture-level abstractions: the services it uses; the main business and data components and how these relate. So it would be good if similar high-level abstractions could be derived and presented automatically by analyzing and monitoring the execution of your application. Model elements would include application components, the application server services they use, and the data access, transaction management, and calling relationships between them.

Once application model elements were identified they would be updated dynamically during execution. Monitoring the changing patterns of inter-relationships in the model would automatically detect construction-quality problems by detecting unlikely relationships, unnecessary and duplicated relationships, and undesirable model entity states. Instead of trying to spot problems in the clutter of source code we could see key abstractions directly in the model.

eoLogic terms this form of indirect application monitoring Derived Model Analysis (DMA): tools analyze Java EE applications both statically and during server execution to derive an abstract model that includes both application components and Java EE services. Subsequent changes to the model form a dynamic event sequence that can be used to (a) track and validate application execution and (b) visualize the model. Lower-level application execution details can be recorded in the context of the sequence of model changes.

Note that DMA is not a profiling technique - it doesn't aim to identify current code hotspots; instead, it analyses how services have been constructed and are being used. The idea is to identify places where hotspots or unreliability may occur under load. This deeper form of analysis can be used to find problems before they manifest themselves and without the application being loaded during testing. These problems include incorrect or inefficient transaction grouping, inefficient database access, unreliable sequences of inter-component communication, and failure to control service lifecycles correctly. There's no need to drive the application to a point at which it exhibits slowdown, and the results need little interpretation.

Deriving a DMA Model
To generate and validate an abstract model of an application a tool must be able to monitor events in the server and interpret them in light of the relevant stored knowledge.

This includes definitions of the main abstract entities we're interested in (transaction manager, transaction resources, transactions, EJB containers, JMS destinations, etc.), the possible relationships between these entities, and invalid and valid patterns of relationships and states. DMA forms them into an abstract Entity-Relationship-Attribute (ERA) model as the system executes, with model changes triggering annotated definitions of problem states.

Relationship to JMX
The model sounds a lot like Java Management Extensions (JMX) - which essentially define a form of abstract model for purposes of managing and monitoring Java applications, and it suggests that possibly DMA could be layered on top of the information available from JMX MBeans. In detail, what characteristics does a DMA model require?

  • It must be an accurate and complete abstract model of an application, linking static (source) and runtime application components.
  • It must be able to be updated in real-time as the server executes generating meaningful sequential event flows.
  • It must support a wide range of relationship types including application-level call relationships.
  • It must be able to be intimately combined with knowledge about valid and potentially invalid model forms.
  • It must be possible to relate model-level information easily back to application source.
  • It must be easily filtered to focus on different aspects of server operation.
  • And it must be easily and intuitively understood.
JMX goes some way towards what is needed: It provides an abstract model of an application for both its static and dynamic aspects; it allows easy selection of MBeans; many MBeans relate directly to easily understood aspects of server operation; there's a notification system for attribute changes and there's even an MBean relation service.

However, for our purposes it also has some serious limitations. Many of the relationships we have to monitor are based on calling sequences and application component relationships. Designed primarily for system management and threshold monitoring, JMX doesn't provide the source-level monitoring and mapping that the detection and (especially) the explanation of application construction errors requires. Also, the level of coverage is generally insufficiently detailed to provide a coherent execution model for the purposes of visualization. And if we want to use the product to investigate problems requiring the ability to freeze the server at the point of problem detection and extract stack and related data information then JMX isn't precise enough.

So the approach that we adopted is to create a more detailed runtime ERA model specialized for the following purposes:

  • Representing sequences of server operation precisely and clearly
  • Detecting construction errors based on component interrelations, including call sequences and transaction membership
  • Explaining construction errors by relating model entities and relationships to precise source references
  • Providing an intuitive visual model of sequential server operation
  • Supporting model tracing and playback
  • Supporting integrated debugging
This specialized model then provides the structure for attaching knowledge about model entity roles and valid and invalid patterns of model relationships and attributes, together with details on problem descriptions and suggested fixes.

The need for detailed tracking of calls and object states means that the DMA engine moves from the realm of JMX and more towards an application of Aspect-Oriented Programming (AOP), combining the planned abstraction of JMX with the detailed and flexible monitoring and intervention of AOP. Having said this, it would be wasteful not to exploit the JMX information provided by a server. Some JMX MBeans serve as important internal DMA monitoring and access points, but are augmented with additional monitoring and updating points in the server.

DMA Error Detection
As shown in Figure 1 DMA abstracts from the underlying framework and application objects to a conceptual ERA model. Queries against this model then provide the means for problem recognition.

Usually the abstraction stage is primarily one of selection as key objects are monitored, but it can also require composition of elements from more than one underlying object.

DMA Use Case
To look at how the abstraction mechanisms of DMA allow construction problems to be detected and explained let's look at it operating on a sample application. We'll aim to show how we can identify a pattern of application and framework components that indicates a problem. We'll then show how the problem can be visualized and explained back to the source level by exploring the model at the point of detection.

Example Application
Figure 2 shows a simple Web-based order-processing example that accepts orders and processes them in the following way:

  • An order invoice is created and queued to an existing invoice service using JMS to create and process the invoice.
  • The order details are queued to an order processing system using JMS to process and deliver the order separately.
However there's a problem: The invoices don't arrive at the invoice processing application although the order entries are processed correctly.

Monitoring the Application
To monitor the sample application we'll run the WebLogic server from our DMA analyzer called eoSense, which comprises a server agent and a client. The agent constructs and checks the abstract model as WebLogic executes. When a problem is detected, the agent signals an alert to the client.

Transaction-Related Alerts
Running the example application results in the initial alerts shown in Figure 3 being detected (after several less serious alerts).

Looking at the alerts in more detail, there was a:

  • JMS Message sent inside a JTA Transaction using a non-XA Connection - A JMS Connection created from a non-XA Factory was used to create a JMS session and sender. The sender was then used with the context of a JTA transaction. This may indicate that an XA JMS Connection should have been used instead.
  • Mixed Transactions - The JMS sender has been used from a JMS Session marked as transacted, but there's already a JTA transaction active on the current thread.
DMA Visualization
When the Mixed Transaction alert is recorded a diagram of the ERA model allows the context of the problem to be understood. In eoSense this is called the Server View and an image of the server view is shown in Figure 4.

We can see that there are two active transactions, one linked to the Order Processing Servlet and the other linked to a JMS Session. We can also see that the Order Processing Servlet has communicated with two JMS Senders. Figure 5 shows diagrammatically the named key entities and relationships from Figure 4.

  • There are two in-flight transactions held by the Transaction Manager
  • There is an "initiated By" relationship between the OrderProcessingExample Servlet and Transaction 1
  • There is an "Initiated By" relationship between the JMS Session 1 and Transaction 2
  • The OrderProcessingExample Servlet has sent two Messages: There is a "Has_Called" relationship to JMS Sender 1, which is attached to the Order JMS Destination, and a "Has_Called" Relationship to JMS Sender 2, which is attached to the Invoice JMS Destination.

More Stories By Alan West

Alan West is CTO of eoLogic (http://www.eologic.com), responsible for all product development. He was previously a founder of Object Software Technology Ltd, and has over 20 years of experience in software tool design and architecting large software systems.

More Stories By Gordon Cruickshank

Gordon Cruickshank is co-founder of eoLogic (http://www.eologic.com), a software tools company created to develop innovative testing and debugging solutions. He was previously development manager at Wind River Systems and Objective Software Technology, building C++ debugging and object visualization tools.

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
n d 08/22/06 10:36:16 AM EDT

This article introduces a new form of analysis for Java EE applications: a runtime abstract application model derived automatically from an application server using stored knowledge of Java EE construction. The model is used dynamically to do extensive automatic checks for a range of construction errors that could produce poor performance or unreliability. The model also lets server behavior be dynamically visualized in real-time or retrospectively.

@ThingsExpo Stories
Is your aging software platform suffering from technical debt while the market changes and demands new solutions at a faster clip? It’s a bold move, but you might consider walking away from your core platform and starting fresh. ReadyTalk did exactly that. In his General Session at 19th Cloud Expo, Michael Chambliss, Head of Engineering at ReadyTalk, will discuss why and how ReadyTalk diverted from healthy revenue and over a decade of audio conferencing product development to start an innovati...
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, discussed the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filterin...
Early adopters of IoT viewed it mainly as a different term for machine-to-machine connectivity or M2M. This is understandable since a prerequisite for any IoT solution is the ability to collect and aggregate device data, which is most often presented in a dashboard. The problem is that viewing data in a dashboard requires a human to interpret the results and take manual action, which doesn’t scale to the needs of IoT.
So, you bought into the current machine learning craze and went on to collect millions/billions of records from this promising new data source. Now, what do you do with them? Too often, the abundance of data quickly turns into an abundance of problems. How do you extract that "magic essence" from your data without falling into the common pitfalls? In her session at @ThingsExpo, Natalia Ponomareva, Software Engineer at Google, provided tips on how to be successful in large scale machine learning...
What does it look like when you have access to cloud infrastructure and platform under the same roof? Let’s talk about the different layers of Technology as a Service: who cares, what runs where, and how does it all fit together. In his session at 18th Cloud Expo, Phil Jackson, Lead Technology Evangelist at SoftLayer, an IBM company, spoke about the picture being painted by IBM Cloud and how the tools being crafted can help fill the gaps in your IT infrastructure.
"C2M is our digital transformation and IoT platform. We've had C2M on the market for almost three years now and it has a comprehensive set of functionalities that it brings to the market," explained Mahesh Ramu, Vice President, IoT Strategy and Operations at Plasma, in this SYS-CON.tv interview at @ThingsExpo, held June 7-9, 2016, at the Javits Center in New York City, NY.
"delaPlex is a software development company. We do team-based outsourcing development," explained Mark Rivers, COO and Co-founder of delaPlex Software, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
Traditional IT, great for stable systems of record, is struggling to cope with newer, agile systems of engagement requirements coming straight from the business. In his session at 18th Cloud Expo, William Morrish, General Manager of Product Sales at Interoute, outlined ways of exploiting new architectures to enable both systems and building them to support your existing platforms, with an eye for the future. Technologies such as Docker and the hyper-convergence of computing, networking and sto...
SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
It’s 2016: buildings are smart, connected and the IoT is fundamentally altering how control and operating systems work and speak to each other. Platforms across the enterprise are networked via inexpensive sensors to collect massive amounts of data for analytics, information management, and insights that can be used to continuously improve operations. In his session at @ThingsExpo, Brian Chemel, Co-Founder and CTO of Digital Lumens, will explore: The benefits sensor-networked systems bring to ...
SYS-CON Events announced today the Enterprise IoT Bootcamp, being held November 1-2, 2016, in conjunction with 19th Cloud Expo | @ThingsExpo at the Santa Clara Convention Center in Santa Clara, CA. Combined with real-world scenarios and use cases, the Enterprise IoT Bootcamp is not just based on presentations but with hands-on demos and detailed walkthroughs. We will introduce you to a variety of real world use cases prototyped using Arduino, Raspberry Pi, BeagleBone, Spark, and Intel Edison. Y...
Large scale deployments present unique planning challenges, system commissioning hurdles between IT and OT and demand careful system hand-off orchestration. In his session at @ThingsExpo, Jeff Smith, Senior Director and a founding member of Incenergy, will discuss some of the key tactics to ensure delivery success based on his experience of the last two years deploying Industrial IoT systems across four continents.
Much of IT terminology is often misused and misapplied. Modernization and transformation are two such terms. They are often used interchangeably even though they mean different things and have very different connotations. Indeed, it is somewhat safe to assume that in IT any transformative effort is likely to also have a modernizing effect, and thus, we can see these as levels of improvement efforts. However, many businesses are being led to believe if they don’t transform now they risk becoming ...
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
"Tintri was started in 2008 with the express purpose of building a storage appliance that is ideal for virtualized environments. We support a lot of different hypervisor platforms from VMware to OpenStack to Hyper-V," explained Dan Florea, Director of Product Management at Tintri, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
"There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...