Click here to close now.

Welcome!

Java Authors: Liz McMillan, Harry Trott, Carmen Gonzalez, Pat Romanski, Yeshim Deniz

Related Topics: Java

Java: 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
While great strides have been made relative to the video aspects of remote collaboration, audio technology has basically stagnated. Typically all audio is mixed to a single monaural stream and emanates from a single point, such as a speakerphone or a speaker associated with a video monitor. This leads to confusion and lack of understanding among participants especially regarding who is actually speaking. Spatial teleconferencing introduces the concept of acoustic spatial separation between conference participants in three dimensional space. This has been shown to significantly improve comprehe...
SYS-CON Events announced today that the "First Containers & Microservices Conference" will take place June 9-11, 2015, at the Javits Center in New York City. The “Second Containers & Microservices Conference” will take place November 3-5, 2015, at Santa Clara Convention Center, Santa Clara, CA. Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities.
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? In this Power Panel at DevOps Summit, moderated by Jason Bloomberg, the leading expert on architecting agility for the enterprise and president of Intellyx, panelists will peel away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud environment, and we must architect and code accordingly. At the very least, you'll have no problem fil...
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...
The 4th International Internet of @ThingsExpo, co-located with the 17th International Cloud Expo - to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA - announces that its Call for Papers is open. The Internet of Things (IoT) is the biggest idea since the creation of the Worldwide Web more than 20 years ago.
Since 2008 and for the first time in history, more than half of humans live in urban areas, urging cities to become “smart.” Today, cities can leverage the wide availability of smartphones combined with new technologies such as Beacons or NFC to connect their urban furniture and environment to create citizen-first services that improve transportation, way-finding and information delivery. In her session at @ThingsExpo, Laetitia Gazel-Anthoine, CEO of Connecthings, will focus on successful use cases.
The Internet of Things promises to transform businesses (and lives), but navigating the business and technical path to success can be difficult to understand. In his session at @ThingsExpo, Sean Lorenz, Technical Product Manager for Xively at LogMeIn, demonstrated how to approach creating broadly successful connected customer solutions using real world business transformation studies including New England BioLabs and more.
Sensor-enabled things are becoming more commonplace, precursors to a larger and more complex framework that most consider the ultimate promise of the IoT: things connecting, interacting, sharing, storing, and over time perhaps learning and predicting based on habits, behaviors, location, preferences, purchases and more. In his session at @ThingsExpo, Tom Wesselman, Director of Communications Ecosystem Architecture at Plantronics, will examine the still nascent IoT as it is coalescing, including what it is today, what it might ultimately be, the role of wearable tech, and technology gaps stil...
One of the biggest impacts of the Internet of Things is and will continue to be on data; specifically data volume, management and usage. Companies are scrambling to adapt to this new and unpredictable data reality with legacy infrastructure that cannot handle the speed and volume of data. In his session at @ThingsExpo, Don DeLoach, CEO and president of Infobright, will discuss how companies need to rethink their data infrastructure to participate in the IoT, including: Data storage: Understanding the kinds of data: structured, unstructured, big/small? Analytics: What kinds and how responsiv...
Today’s enterprise is being driven by disruptive competitive and human capital requirements to provide enterprise application access through not only desktops, but also mobile devices. To retrofit existing programs across all these devices using traditional programming methods is very costly and time consuming – often prohibitively so. In his session at @ThingsExpo, Jesse Shiah, CEO, President, and Co-Founder of AgilePoint Inc., discussed how you can create applications that run on all mobile devices as well as laptops and desktops using a visual drag-and-drop application – and eForms-buildi...
Advanced Persistent Threats (APTs) are increasing at an unprecedented rate. The threat landscape of today is drastically different than just a few years ago. Attacks are much more organized and sophisticated. They are harder to detect and even harder to anticipate. In the foreseeable future it's going to get a whole lot harder. Everything you know today will change. Keeping up with this changing landscape is already a daunting task. Your organization needs to use the latest tools, methods and expertise to guard against those threats. But will that be enough? In the foreseeable future attacks w...
17th Cloud Expo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, 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. Meanwhile, 94% of enterprises are using some form of XaaS – software, platform, and infrastructure as a service.
Cloud is not a commodity. And no matter what you call it, computing doesn’t come out of the sky. It comes from physical hardware inside brick and mortar facilities connected by hundreds of miles of networking cable. And no two clouds are built the same way. SoftLayer gives you the highest performing cloud infrastructure available. One platform that takes data centers around the world that are full of the widest range of cloud computing options, and then integrates and automates everything. Join SoftLayer on June 9 at 16th Cloud Expo to learn about IBM Cloud's SoftLayer platform, explore se...
The explosion of connected devices / sensors is creating an ever-expanding set of new and valuable data. In parallel the emerging capability of Big Data technologies to store, access, analyze, and react to this data is producing changes in business models under the umbrella of the Internet of Things (IoT). In particular within the Insurance industry, IoT appears positioned to enable deep changes by altering relationships between insurers, distributors, and the insured. In his session at @ThingsExpo, Michael Sick, a Senior Manager and Big Data Architect within Ernst and Young's Financial Servi...
15th Cloud Expo, which took place Nov. 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA, expanded the conference content of @ThingsExpo, Big Data Expo, and DevOps Summit to include two developer events. IBM held a Bluemix Developer Playground on November 5 and ElasticBox held a Hackathon on November 6. Both events took place on the expo floor. The Bluemix Developer Playground, for developers of all levels, highlighted the ease of use of Bluemix, its services and functionality and provide short-term introductory projects that developers can complete between sessions.
The 3rd International @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 – is now accepting Hackathon proposals. Hackathon sponsorship benefits include general brand exposure and increasing engagement with the developer ecosystem. At Cloud Expo 2014 Silicon Valley, IBM held the Bluemix Developer Playground on November 5 and ElasticBox held the DevOps Hackathon on November 6. Both events took place on the expo floor. The Bluemix Developer Playground, for developers of all levels, highlighted the ease of use of...
In the consumer IoT, everything is new, and the IT world of bits and bytes holds sway. But industrial and commercial realms encompass operational technology (OT) that has been around for 25 or 50 years. This grittier, pre-IP, more hands-on world has much to gain from Industrial IoT (IIoT) applications and principles. But adding sensors and wireless connectivity won’t work in environments that demand unwavering reliability and performance. In his session at @ThingsExpo, Ron Sege, CEO of Echelon, will discuss how as enterprise IT embraces other IoT-related technology trends, enterprises with i...
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...
We’re no longer looking to the future for the IoT wave. It’s no longer a distant dream but a reality that has arrived. It’s now time to make sure the industry is in alignment to meet the IoT growing pains – cooperate and collaborate as well as innovate. In his session at @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, will examine the key ingredients to IoT success and identify solutions to challenges the industry is facing. The deep industry expertise behind this presentation will provide attendees with a leading edge view of rapidly emerging IoT oppor...
The industrial software market has treated data with the mentality of “collect everything now, worry about how to use it later.” We now find ourselves buried in data, with the pervasive connectivity of the (Industrial) Internet of Things only piling on more numbers. There’s too much data and not enough information. In his session at @ThingsExpo, Bob Gates, Global Marketing Director, GE’s Intelligent Platforms business, to discuss how realizing the power of IoT, software developers are now focused on understanding how industrial data can create intelligence for industrial operations. Imagine ...