Technical Program
This year's Technical Papers track comprises 26 presentations of the latest, top-rate academic and industrial research results. (Please note that, in an unusual move, we have arranged for one of the Technical Papers to be presented as part of the Onward! track because of a natural affinity with one of the Onward! presentations.) |
Tuesday, 28 October
Wednesday, 29 October
Thursday, 30 October
Free Culture: The limited but essential role of property in building an environment for creativityTuesday, 28 October – 8:30-10:00 |
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This talk will sketch the boundaries of protection that intellectual property law should set, but argue that extremism has now defeated these limits. The consequence is an environment within which modular creativity is increasingly constrained.
Presenter
Lawrence Lessig is a Professor of Law at Stanford Law School and founder of the school's Center for Internet and Society. He is one of the country's leading commentators on legal aspects of new communications technologies and cyberspace. He is Professor of Law and founder and executive director of the Center for Internet and Society at Stanford Law School. Professor Lessig teaches and writes in the areas of constitutional law, law and high technology, Internet regulation, comparative constitutional law, and the law of cyberspace.
He is the author of many influential publications about cyberlaw and cyberspace, including two books: The Future of Ideas: The Fate of the Commons in a Connected World (2001) and Code and Other Laws of Cyberspace (1999).
Refactoring and ReflectionTuesday, 28 October – 10:30-12:00 |
10:30 - 11:00 |
Language-Independent Aspect-Oriented ProgrammingDonal Lafferty,
Trinity College Dublin,
Donal.Lafferty@cs.tcd.ie
The term aspect-oriented programming (AOP) has come to describe the set of programming mechanisms developed specifically to express crosscutting concerns. Since crosscutting concerns cannot be properly modularized within object-oriented programming (OOP), they are expressed as aspects and are composed, or woven, with traditionally encapsulated functionality referred to as components. Many AOP models exist, but their implementations are typically coupled with a single language. To allow weaving of existing components with aspects written in the language of choice, AOP requires a language-independent tool. This paper presents Weave.NET, a load-time weaver that allows aspects and components to be written in a variety of languages and freely intermixed. Weave.NET relies on XML to specify aspect bindings and ECMA Common Language Infrastructure to avoid coupling aspects or components with a particular language. By demonstrating language-independence, Weave.NET provides a migration path to the AOP paradigm by preserving existing developer knowledge, tools and software components. The tool's capabilities are demonstrated with logging aspects written with and applied to Visual Basic and C# components. |
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11:00 - 11:30 |
Refactoring for Generalization Using Type ConstraintsFrank Tip,
IBM T.J. Watson Research Center,
tip@watson.ibm.com
Refactoring is the process of applying behavior-preserving transformations (called "refactorings") in order to improve a program's design. Associated with a refactoring is a set of preconditions that must be satisfied to guarantee that program behavior is preserved, and a set of source code modifications. An important category of refactorings is concerned with generalization (e.g., "Extract Interface" for re-routing the access to a class via a newly created interface, and "Pull Up Members" for moving members into a superclass). For these refactorings, both the preconditions and the set of allowable source code modifications depend on interprocedural relationships between types of variables. We present an approach in which type constraints are used to verify the preconditions and to determine the allowable source code modifications for a number of generalization-related refactorings. This work is implemented in the standard distribution of Eclipse (see www.eclipse.org). |
11:30 - 12:00 |
Partial Behavioral Reflection: Spatial and Temporal Selection of ReificationEric Tanter,
University of Chile, École des Mines de Nantes/INRIA,
Eric.Tanter@emn.fr
Behavioral reflection is a powerful approach for adapting the behavior of running applications. In this paper we present and motivate partial behavioral reflection, an approach to more efficient and flexible behavioral reflection. We expose the spatial and temporal dimensions of such reflection. In the context of Java, we present a reflective architecture offering appropriate interfaces for static and dynamic configuration of partial behavioral reflection at various levels, as well as an open reflective extension for Java implementing this architecture. Reflex is the first extension that fully supports partial behavioral reflection in a portable manner, and that seamlessly integrates load-time and runtime behavioral reflection, along with static optimizations. The paper shows preliminary benchmarks and examples supporting the approach. The examples, dealing with the observer pattern and asynchronous communication via transparent futures, also show the interest of partial behavioral reflection as a tool for open dynamic aspect-oriented programming. |
Meeting the Challenge of Software Engineering Education for Working Professionals in the 21st CenturyTuesday, 28 October – 10:30-12:00 |
Software engineering education for working professionals remains a challenge from the perspective of determining relevant content; identifying effective methods for delivery; and maintaining the focus and motivation of students. This panel brings together academic and industry professionals to share their perspectives and experiences. Anticipated points for discussion include: education/training delivery strategies, curriculum definition, marketing issues, collaboration strategies to engage industry sponsorship, value assessments for students and sponsoring organizations, and program success stories. This will be a highly interactive panel and the audience should come prepared to both ask and answer questions.
Naturalistic Programming and Run-Time Code GenerationTuesday, 28 October – 10:30-12:00 |
These papers explore simplifying programming by examining some of our underlying assumptions about references and constructing programs.
Beyond AOP: Toward Naturalistic ProgrammingCristina Lopes,
University of California, Irvine,
lopes@ics.uci.edu
Software understanding (for documentation, maintenance or evolution) is one of the longest-standing problems in Computer Science. The use of bct-oriented languages helps, but fundamentally remains far from solving the problem. Most programming languages and systems have fallen prey to the assumption that they are supposed to capture idealized models of computation inspired by deceptively simple metaphors such as objects and mathematical functions. Aspect-oriented programming languages have made a significant breakthrough by noticing that, in many situations, humans think and describe in crosscutting terms. In this paper we suggest that the next breakthrough would require looking even closer to the way humans have been thinking and describing complex systems for thousand of years using natural languages. While natural languages themselves are not appropriate for programming, they contain a number of elements that make descriptions concise, effective and understandable. In particular, natural languages referentiality is a key factor in supporting powerful program organizations that can be more easily understood by humans. |
Routine Run-time Code GenerationSam Kamin, Univ. of Illinois at Urbana-Champaign, kamin@cs.uiuc.edu
The decades-old paradigm of "object code = executable code: is outdated. The paradigm we propose in this paper is "object code = executable program generator.: Similarly, "software component" should be "program that, when appropriately invoked by a client, generates machine language useful to the client." Traditional object files amount to constant functions in the domain of code-producing functions; in the future, we will routinely employ the full domain of higher-order code values. In this paper, we argue that such a change in viewpoint can lead to much wider use of run-time code generation, by overcoming the bureaucratic barriers it usually encounters. Run-time code generation has numerous applications; when it comes to be used routinely, many more applications are likely to be discovered. |
Grid-supported Communications ApplicationsTuesday, 28 October – 13:30-15:00 |
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This invited talk will describe how emerging distributed computing systems could mutate into the communications systems of the future. Armed with high speed interconnect, and software elements that assign, track and charge for geographically distributed computing resources, these systems could just as easily compute and deliver an image to a remote location (for human communications) as perform an internal streaming file transfer. With this kind of capability not tied to the user's premises, customer equipment could be very asset light and still deliver very high end services like realtime processed video. Using as an example MIRAGE II, a data mining system with a geographically distributed, remotely computed Augmented Reality interface, a prototype built by Motorola in association with NCSA, Labedz will discuss the main hurdles along the way to communications systems dependent on real-time remote computing and high speed networks.
Speaker
Gerry Labedz has worked at Motorola for 28 years in the areas of mobile and cellular radio hardware and software. He worked on the first microprocessor controlled radio in the '70s, the first digital cellular system in the '80s, and the world's most accurate parallel-computed cellular system simulation tool in the '90s. He holds 23 patents in the areas of radio signaling, system design and visualization, and large-scale real-time simulation for cellular system control. During the 1990s, he and his group were the largest industrial users of the supercomputer facilities at the National Center for Supercomputing Applications (NCSA). He holds the title of Dan Noble Fellow, Motorola's highest technical honor. Most recently he has led a project centering on Hyperfast Computational Communications, or HyperComputiCations
Xtreme Programming and Agile CoachingTuesday, 28 October – 15:30-17:00 |
This panel brings together coaches to discuss all aspects of the practice: how to become a coach, choosing a coach, and describing what is to be an (in) effective coach. A coach watches, provides feedback, and suggests subtle direction. The coach may be more—for example—an architect or team lead—but that is a matter for debate. This session will be run as a panel with two open "fish bowl" seats, only one of which may be occupied by audience members at any one time. The panelists will defend their positions and offer feedback. Panelists were asked to offer their observations on three questions: How did YOU become a coach? What's the toughest thing you've had to do as a coach? What's your advice for teams looking for a coach?
ToolsTuesday, 28 October – 15:30-17:00 |
15:30 - 16:00 |
Experience in Developing the UrbanSim System: Tools for Developing Research Software for a Politically Charged DomainBjorn Freeman-Benson,
Center for Urban Simulation and Policy Analysis, University of Washington,
bnfb@cs.washington.edu
UrbanSim is a sophisticated simulation system for modeling urban land use, transportation, and environmental impacts, over a period of 20 or more years, under alternate possible scenarios. Our purpose is to support democratic decision-making on such issues as building new transit systems or freeways, or changing zoning or economic incentives, as well as on broader issues such as sustainable, livable cities, economic vitality, social equity, and environmental preservation. The domain is politically charged, with different stakeholders bringing strongly held values to the table. Our goal is not to favor any particular stakeholder values, but rather to let the stakeholders evaluate the results themselves. This need for neutrality has several implications for the development process, among other things resulting in our choice of an open source/open process model. UrbanSim is also an NSF-funded infrastructure project with a mix of research and development goals. Unlike most academic projects, this one has real customers (municipal planning organizations) with real needs. Thus the UrbanSim project has a number of simultaneous goals, which are in some tension: producing credible, reliable code; utilizing a flexible process that adapts to new research discoveries; maintaining coherent architecture and continuous development progress; and using part-time and inexperienced student staff in addition to experienced full-time staff. (This is in contrast to the usual model in XP and other agile development processes, in which all developers are considered equally experienced and skilled.) In this report, we discuss the tools we have chosen, modified, or developed in-house; and the reasons why these tools are good choices for this mixed research/product development environment. Our tools include: Eclipse, MySQL, CVS, Ant, Fireman (a Tinderbox-like automatic build and test system), JUnit, FIT, Wiki, Bugzilla, a physical traffic light, and a daily project dashboard. The tools are tightly integrated and collectively support our agile process. |
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16:00 - 16:30 |
Experiences using an ODBMS for a high-volume internet banking systemVincent Coetzee,
eBucks.com,
vincent.coetzee@ebucks.com Few large corporate organizations make the decision to use an Object Database Management System (ODBMS) when developing high volume transactional eCommerce web sites. This report examines the architecture used to power a website that encompasses banking, online shopping, and the management of a Customer Loyalty Currency called eBucks. This system proves that an ODBMS can be used in a high volume transactional system with great success. While the choice of this technology has many merits, there are drawbacks. These drawbacks are examined along with the solutions that have been used at eBucks to either solve or ameliorate them. |
SmalltalkianaTuesday, 28 October – 15:30-16:30 |
15:30 - 16:00 |
Applying Traits to the Smalltalk Collection ClassesAndrew P. Black,
OGI School of Science & Engineering, Oregon Health & Science University,
black@cse.ogi.edu
Traits are a programming language technology modeled after mixins but avoiding their problems. This paper reports on a refactoring of the Smalltalk collections classes using traits. We observed that the original collection classes contained much duplication of code; traits let us remove all of it. We also found places where the protocols of the collections lacked uniformity; traits allow us to correct these non-uniformities without code duplication. In addition, traits make possible more general reuse of collection code outside of the existing hierarchy; for example, they make it easy to convert other collection-like things into true collections. Our refactoring reduced the number of methods in the collection classes by approximately 10 per cent. More importantly, understandability and reusability of the code was significantly improved. |
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16:00 - 16:30 |
OOPAL: Integrating Array Programming in Object-Oriented ProgrammingPhilippe Mougin,
pmougin@acm.org
Array programming shines in its ability to express computations at a high-level of abstraction, allowing one to manipulate and query whole sets of data at once. This paper presents the OOPAL model that enhances object-oriented programming with array programming features. The goal of OOPAL is to determine a minimum set of modifications that must be made to the traditional object model in order to take advantage of the possibilities of array programming. It is based on a minimal extension of method invocation and the definition of a kernel of methods implementing the fundamental array programming operations. The model is validated in F-Script, a new scripting language. |
Seven Paradoxes of Object-Oriented Programming LanguagesWednesday, 29 October – 8:30-10:00 |
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Although many of us have worked to create good object-oriented programming languages, it would be hard to say (with a straight face) that any of our creations have totally succeeded. Why not? I believe that this endeavor is essentially paradoxical. Thus, whenever a language designer pursues a particular goal and loses sight of the lurking paradox, the outcome is an all too often fatally flawed result. One way to think about this is to explore the following seven paradoxes:
- Because programming languages, development environments, and execution engines are intended for both people and computers, they must both humanize and dehumanize us.
- Adding a richer set of concepts to a programming language impoverishes its universe of discourse.
- Putting a language's cognitive center in a more dynamic place reduces the verbiage needed to accomplish a task, even though less information can be mechanically deduced about the program.
- The most concrete notions are the most abstract, and pursuing comfort or correctness with precision leads to fuzziness.
- Although a language, environment, and execution engine are designed for the users' minds, the experience of use will alter the users' minds.
- Object-oriented programming has its roots in modeling and reuse, yet these notions do not coincide and even conflict with each other.
- A language designed to give programmers what they want may initially succeed but create pernicious problems as it catches on. However, a language designed to give programmers what they really need may never catch fire at all.
Many of these assertions seem nonsensical, misguided, or just plain wrong. Yet, a deeper understanding of these paradoxes can point the way to better designs for object-oriented programming languages.
Technical Papers and Onward!: Error RepairWednesday, 29 October – 10:30-12:00 |
11:30 - 12:00 |
Automatic Detection and Repair of Errors in Data StructuresBrian Demsky,
MIT Laboratory for Computer Science,
bdemsky@mit.edu
We present a system that accepts a specification of key data structure constraints, then dynamically detects and repairs violations of these constraints, enabling the program to continue to execute productively even in the face of otherwise crippling errors. Our experience using our system indicates that the specifications are relatively easy to develop once one understands the data structures. Furthermore, for our set of benchmark applications, our system can effectively repair errors to deliver consistent data structures that allow the program to continue to operate successfully within its designed operating envelope. |
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GenericsWednesday, 29 October – 10:30-12:00 |
10:30 - 11:00 |
A First-Class Approach to GenericityEric Allen,
Rice University,
eallen@cs.rice.edu
This paper describes how to add first class generic types—including mixins—to strongly-typed, object-oriented languages with nominal (name-based) subtyping such as Java and C#. A generic type system is "first-class" if generic types can appear in any context where conventional types can appear. In this context, a mixin is simply a generic class that extends one its type parameters, e.g., a class C<T> that extends T. Although mixins of this form are widely used in C++ (via templates), they are clumsy and error-prone because C++ treats mixins as macros, forcing each mixin instantiation to be separately compiled and type-checked. The abstraction embodied in a mixin is never separately analyzed. Our formulation of mixins using first class genericity accommodates sound local (class-by-class) type checking, in the same sense that Java supports local (class-by-class) compilation. A mixin can be fully type-checked given symbol tables for each of the classes that it directly references—the same context in which Java performs incremental class compilation. To our knowledge no previous formal analysis of first-class genericity in languages with nominal type systems has been conducted, which is surprising because nominal type systems have become predominant in mainstream object-oriented programming languages. What makes our treatment of first class genericity particularly interesting and important is the fact that it can be added to the existing Java language without any change to the underlying Java Virtual Machine. Moreover, the extension is backward compatible with legacy Java source and class files. Although our discussion of a practical implementation strategy focuses on Java, the same scheme could be applied to other object-oriented languages such as C# or Eiffel that support incremental compilation, dynamic class loading, and a static type system with nominal subtyping. |
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11:00 - 11:30 |
A Comparative Study of Language Support for Generic ProgrammingRonald Garcia,
Indiana University,
garcia@osl.iu.edu
Many modern programming languages support basic generic programming, sufficient to implement type-safe polymorphic containers. Some languages have moved beyond this basic support to a broader, more powerful interpretation of generic programming, and their extensions have proven valuable in practice. This paper reports on a comprehensive comparison of generics in six programming languages: C++, Standard ML, Haskell, Eiffel, Java (with its proposed generics extension), and Generic C#. By implementing a substantial example in each of these languages, we identify eight language features that support this broader view of generic programming. We find these features are necessary to avoid awkward designs, poor maintainability, unnecessary run-time checks, and painfully verbose code. As languages increasingly support generics, it is important that language designers understand the features necessary to provide powerful generics and that their absence causes serious difficulties for programmers. |
11:30 - 12:00 |
Lightweight Confinement for Featherweight JavaTian Zhao,
University of Wisconsin, Milwaukee,
tzhao@cs.uwm.edu
Confinement properties impose a structure on object graphs which can be used to enforce encapsulation— which is essential to certain program optimizations, to modular reasoning, and in many cases to software assurance. This paper formalizes the notion of confined type in the context of Featherweight Java. A static type system that mirrors the informal rules of Vitek and Bokopwski is proposed and proven sound. The definition of confined types is extended to confined instantiation of generic classes. Thus allowing for confined collection types in Java and for classes that can be confined post hoc. Confinement types rules are given for Generic Featherweight Java, and proven sound. |
Discipline and Practices of TDD (Test Driven Development)Wednesday, 29 October – 10:30-12:00 |
This panel brings together practitioners with experience in Agile and XP methodologies to discuss the approaches and benefits of applying Test Driven Development (TDD). The goal of TDD is clean code that works. The mantra of TDD is: write a test; make it run; and make it right. Open questions to be addressed by the panel include:
- How are TDD approaches to be applied to databases, GUIs, and distributed systems?
- What are the quantitative benchmarks that can demonstrate the value of TDD, and
- What are the best approaches to solve the ubiquitous issue of scalability?
Acceptability-Oriented ComputingWednesday, 29 October – 10:30-12:00 |
These papers talk about a new approach to constructing software systems in which the designer identifies key properties that the execution must satisfy to be acceptable to its users. The resulting system consists of layers of components enforcing the acceptability properties.
Acceptability-Oriented ComputingMartin Rinard, MIT, rinard@lcs.mit.edu
We propose a new approach to the construction of software systems. Instead of attempting to build a system that is as free of errors as possible, we instead propose that the designer identify key properties that the execution must satisfy to be acceptable to its users. The developer then augments the system with a layered set of components, each of which enforces one of the acceptability properties. The potential advantages of this approach include more flexible, resilient systems that recover from errors and behave acceptably across a wide range of operating environments, an appropriately prioritized investment of engineering resources, and reduced development costs because of the ability to productively incorporate unreliable components into the final software system and to use less skilled implementors in the development process. |
Automatic Detection and Repair of Errors in Data StructuresBrian Demsky,
MIT,
demsky@lcs.mit.edu
We present a system that accepts a specification of key data structure constraints, then dynamically detects and repairs violations of these constraints, enabling the program to continue to execute productively even in the face of otherwise crippling errors. Our experience using our system indicates that the specifications are relatively easy to develop once one understands the data structures. Furthermore, for our set of benchmark applications, our system can effectively repair errors to deliver consistent data structures that allow the program to continue to operate successfully within its designed operating envelope. |
VisionWednesday, 29 October – 10:30-12:00 |
10:30 - 11:00 |
Model Driven Development - The Case for Domain Oriented ProgrammingDave Thomas,
Bedarra Research Labs,
dave@bedarra.com In this paper, we offer an alternative vision for domain driven development (3D). Our approach is model driven and emphasizes the use of generic and specific domain oriented programming (DOP) languages. DOP uses strong specific languages, which directly incorporate domain abstractions, to allow knowledgeable end users to succinctly express their needs in the form of an application computation. Most domain driven development (3D) approaches and techniques are targeted at professional software engineers and computer scientists. We argue that DOP offers a promising alternative. Specifically we are focused on empowering application developers who have extensive domain knowledge as well as sound foundations in their professions, but may not be formally trained in computer science. We provide a brief survey of DOP experiences, which show that many of the best practices such as patterns, refactoring, and pair programming are naturally and ideally practiced in a MDD setting. We compare and contrast DOP with other popular approaches, most of which are deeply rooted in the OO community. Finally we highlight challenges and opportunities in the design and implementation of such languages. |
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11:00 - 11:30 |
An End to End Domain Driven Developement FrameworkAditya Agrawal,
ISIS, Vanderbilt University,
aditya.agrawal@vanderbilt.edu This paper presents a comprehensive, domain-driven framework for development. It consists of a meta-programmable domain-specific modeling environment, and a model transformation and generation toolset based on graph transformations. The framework allows the creation of custom, domain-oriented programming environments that support end-user programmability. In addition, the framework could be considered an early, end-to-end implementation of the concepts advocated by the Model-Driven Architecture of OMG. |
11:30 - 12:00 |
Software Factories: Assembling Applications With Patterns, Models, Frameworks and ToolsJack J. Greenfield,
Microsoft, Visual Studio, Enterprise Frameworks And Tools,
jackgr@microsoft.com The confluence of component based development, model driven development and software product lines forms an approach to application development based on the concept of software factories. This approach promises greater gains in productivity and predictability than those produced by the incremental advances of recent memory, which have not kept pace with rapid innovation in platform technology. Focusing on development by assembly using domain specific languages, patterns, models, frameworks and tools, software factories make systematic reuse cost effective for many applications, enabling the formation of supply chains and opening the door to mass customization. |
Java PerformanceWednesday, 29 October – 13:30-15:00 |
13:30 - 14:00 |
Dynamic Metrics for JavaBruno Dufour,
McGill University,
bdufou1@cs.mcgill.ca
In order to perform meaningful experiments in optimizing compilation and run-time system design, researchers usually rely on a suite of benchmark programs of interest to the optimization technique under consideration. Programs are described as numeric, memory-intensive, concurrent, or object-oriented, based on a qualitative appraisal, in some cases with little justification. We believe it is beneficial to quantify the behavior of programs with a concise and precisely defined set of metrics, in order to make these intuitive notions of program behavior more concrete and subject to experimental validation. We therefore define a set of unambiguous, dynamic, robust and architecture-independent metrics that can be used to categorize programs according to their dynamic behavior in five areas: size, data structure, memory use, concurrency, and polymorphism. A framework computing some of these metrics for Java programs is presented along with specific results. |
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14:00 - 14:30 |
How Java Programs Interact with Virtual Machines at the Microarchitectural LevelLieven Eeckhout,
Ghent University,
leeckhou@elis.rug.ac.be
Java workloads are becoming increasingly prominent on various platforms ranging from embedded systems, over general-purpose computers to high-end servers. Understanding the implications of all the aspects involved when running Java workloads, is thus extremely important during the design of a system that will run such workloads, to meet its design goals. In other words, understanding the interaction between the Java application, its input and the virtual machine it runs on, is key to a successful design. The goal of this paper is to study this complex interaction at the microarchitectural level, e.g., by analyzing the branch behavior, the cache behavior, etc. This is done by measuring a large number of performance characteristics using performance counters on an AMD K7 Duron microprocessor. These performance characteristics are measured for seven virtual machine configurations, and a collection of Java benchmarks with corresponding inputs coming from the SPECjvm98 benchmark suite, the SPECjbb2000 benchmark suite, the Java Grande Forum benchmark suite and an open-source raytracer, called Raja with 19 scene descriptions. This large amount of data is further analyzed using statistical data analysis techniques, namely principal components analysis and cluster analysis. These techniques provide useful insights in an understandable way. From our experiments, we conclude that (i) the behavior observed at the microarchitectural level is primarily determined by the virtual machine for small input sets, e.g., the SPECjvm98 s1 input set; (ii) the behavior can be quite different for various input sets, e.g., short-running versus long-running benchmarks; (iii) for long-running benchmarks with few hot spots, the behavior can be primarily determined by the Java program and not the virtual machine, i.e., all the virtual machines optimize the hot spots to similarly behaving native code; (iv) in general, the behavior of a Java application running on one virtual machine can be significantly different from running on another virtual machine. These conclusions warn researchers working on Java workloads to be careful when using a limited number of Java benchmarks or virtual machines since this might lead to biased conclusions. |
14:30 - 15:00 |
Effectiveness of Cross-Platform Optimizations for a Java Just-In-Time CompilerKazuaki Ishizaki,
IBM Research, Tokyo Research Laboratory,
ishizaki@trl.ibm.com
We describe the system overview of our Java JIT compiler, which has been the basis for the latest production version of IBM Java virtual machine that supports a diversity of processor architectures including both 32-bit and 64-bit modes, CISC, RISC, and VLIW architectures. In particular, we focus on the design and evaluation of the cross-platform optimizations that are common across different architectures. We study the effectiveness of each optimization by selectively disabling it in our JIT compiler on three different platforms: IA32, IA64, and PowerPC. Based on the detailed statistics, we classify our optimizations and identify a small set of the most cost-effective ones in terms of the performance improvement as the benefit and the compilation time as the cost. In summary, we demonstrate that, with a selected set of optimizations, we can achieve 90% of the peak performance for SPECjvm98 at the expense of only 33% of the total compilation time in comparison to the case in which all the optimizations are enabled. |
Innovate!Wednesday, 29 October – 13:30-15:00 |
Freedom to innovate is one of the key motivators for many technical workers. Unfortunately, although innovation is often trumpeted as a key company attribute, it seems that many organizations struggle to provide the necessary environment—even those organizations whose original claim to fame lay in their ability to innovate. This panel will look at the barriers to innovation that occur in a variety of environments: large, well-established organizations, start-ups, academia, standards bodies and the open source community. Panelists will propose a set of technical and non-technical techniques that can be used to foster innovation in even the most lethargic or hostile environment.
Old CodeWednesday, 29 October – 13:30-15:00 |
13:30 - 14:00 |
Using AspectJ for Component Integration in MiddlewareAdrian Colyer,
IBM UK,
adrian_colyer@uk.ibm.com
This report discusses experiences applying and enhancing AspectJ for a middleware product line at IBM. The purpose of this
effort was to apply Aspect Oriented Programming to cleanly separate components from their execution platforms, while still
allowing them to take advantage of platform-specific facilities for aspects such as error handling, performance monitoring,
and logging. It presents the evolution of the design, implementation, tools support, and approaches used to achieve organizational
buy in.
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14:00 - 14:30 |
Five years of framework building: lessons learnedKurt Madsen, MetaTech, Inc., madsen@tampabay.rr.com When developing large software systems, it is often difficult to foresee exactly which trade-offs are important, and which quality parameters will be of importance down the road. This paper reports experiences from a project in which a large application framework for B2B integration has been continuously developed and used over a five year period. The framework has been the foundation for a variety of different concrete applications; here we will report on our experiences from this endeavor. |
14:30 - 15:00 |
Agile Regression Testing Using Record & PlaybackGerard Meszaros,
ClearStream Consulting,
gerard.meszaros@acm.org There are times when it is not practical to hand-script automated tests for an existing system before one starts to modify it (whether to refactor it to permit automated testing or to add new functionality). In these circumstances, the use of “record & playback” testing may be a viable alternative to hand-writing all the tests. This paper describes experiences using this approach and summarizes key learnings applicable to other projects. |
TechnologyWednesday, 29 October – 13:30-15:00 |
13:30 - 14:00 |
XAspects: An Extensible System for Domain-Specific Aspect LanguagesMacneil Shonle,
Northeastern University,
mshonle@ccs.neu.edu
Current general aspect-oriented programming solutions fall short of
helping the problem of separation of concerns for several concern
domains. Because of this limitation good solutions for these concern
domains do not get used and the opportunity to benefit from
separation of these concerns is missed. By using XAspects, a plug-in
mechanism for domain-specific aspect languages, separation of
concerns can be achieved at a level beyond what is possible for
object-oriented programming languages. As a result, XAspects allows
for certain domain-specific solutions to be used as easily as a new
language feature.
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14:00 - 14:30 |
The Power of Symmetry: Unifying Inheritance and Generative ProgrammingDeLesley Hutchins, MZA Associates Corporation, hutchins@mza.com I present the Ohmu language, a unified object model which allows a number of "advanced" techniques such as aspects, mixin layers, parametric polymorphism, and generative components to be implemented cleanly using two basic concepts: block structure and inheritance. I argue that conventional ways of defining classes and objects have created artificial distinctions which limit their expressiveness. The Ohmu model unifies functions, classes, instances, templates, and even aspects into a single construct – the structure. Function calls, instantiation, aspect-weaving, and inheritance are likewise unified into a single operation – the structure transformation. This simplification eliminates the distinction between classes and instances, and between compile-time and run-time code. Instead of being compiled, programs are reduced using partial evaluation, in which the interpreter is invoked at compile-time. Within this architecture, standard OO inheritance becomes a natural vehicle for creating meta-programs and automatic code generators— the key to a number of recent domain-driven programming methodologies. |
14:30 - 15:00 |
Domain Driven Web Development With WebJinnSergei Kojarski,
Northeastern University,
kojarski@ccs.neu.edu
Web application development cuts across the HTTP protocol, the client-side presentation language (HTML, XML), the server-side technology (Servlets, JSP, ASP, PHP), and the underlying resource (files, database, information system). Consequently, web development concerns including functionality, presentation, control, and structure cross-cut, leading to tangled and scattered code that is hard to develop, maintain, and reuse. In this paper we analyze the cause, consequence, and remedy for this crosscutting. We distinguish between intra-crosscutting that results in code tangling and inter-crosscutting that results in code scattering. To resolve inter-crosscutting, we present a new web application development model named XP that introduces extension points as place-holders for structure-dependent code. We present another model named DDD that incorporates XP into the Model-View-Controller (MVC) model to resolve both intra- and inter-crosscutting. WebJinn is a novel domain-driven web development framework that implements the DDD model. WebJinn has been used to develop web applications at several web sites. Domain driven web development with WebJinn benefits from a significant improvement in code reuse, adaptability, and maintainability. |
Language DesignWednesday, 29 October – 15:30-17:00 |
15:30 - 16:00 |
HydroJ: Object-Oriented Pattern Matching for Evolvable Distributed SystemsKeunwoo Lee,
University of Washington,
klee@cs.washington.edu
In an evolving software system, components must be able to change independently while remaining compatible with their peers. One obstacle to independent evolution is the brittle parameter problem}: the ability of two components to communicate can depend on a number of inessential details of the types, structure, and/or contents of the values communicated. If these details change, then the components can no longer communicate, even if the essential parts of the message remain unaffected. We present HydroJ, an extension of Java that addresses this problem. In HydroJ, components communicate using self-describing, semi-structured messages, and programmers use pattern matching to define the handling of messages. This design stems from two central ideas: first, that self-describing messages reduce dependence on inessential message format details; and second, that object-oriented pattern matching naturally focuses on the essential information in a message and is insensitive to inessential information. We have developed these ideas in the context of Rain, a distributed, heterogeneous messaging system for ubiquitous computing. To evaluate the design, we have constructed a prototype HydroJ compiler, implemented some Rain services in HydroJ, and formalized HydroJ's key features in a core language. |
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16:00 - 16:30 |
Relaxed MultiJava: Balancing Extensibility and Modular TypecheckingTodd Millstein,
University of Washington,
todd@cs.washington.edu
We present the rationale, design, and implementation of Relaxed MultiJava (RMJ), a backward-compatible extension of Java that allows programmers to add new methods to existing classes and to write multimethods. Previous languages supporting these forms of extensibility either restrict their usage to a limited set of programming idioms that can be modularly typechecked (and modularly compiled) or simply forego modular typechecking altogether. In contrast, RMJ supports the new language features in a virtually unrestricted form while still providing modular static typechecking and compilation. In some cases, the RMJ compiler will warn that the potential for a type error exists, but it will still complete compilation. In that case, a custom class loader transparently performs load-time checking to verify that the potential error is never realized. RMJ's compiler and custom loader cooperate to keep load-time checking costs low. We report on our qualitative and quantitative experience with our implementation of RMJ. |
16:30 - 17:00 |
ModJava: A Rational Module System for Java and Its ApplicationsJohn Corwin,
IBM,
jcorwin@us.ibm.com
While Java provides many software engineering benefits, it lacks a coherent module system and instead provides only packages (which are primarily a name space mechanism) and classloaders (which are very low-level). As a result, large Java applications suffer from unexpected interactions between independent components, require complex CLASSPATH definitions, and are often extremely complex to install and maintain. We have implemented a module system for Java that is implemented with class loaders but provides a much higher-level interface. High-level properties can be specified in a module definition and are enforced by the module system as new modules are loaded. To experimentally validate the ability of ModJava to properly handle the complex module inter-relationships found in large Java server systems, we replaced the classloader mechanisms of Apache Tomcat 4.1.18 with 30 ModJava modules. The modified Tomcat is functionally identical to the original, but requires no CLASSPATH definitions, and will operate correctly even if user code loads a different version of a module used by Tomcat, such as the Xerces XML parser. Furthermore, by making a small change to the Java core libraries enabled by ModJava, we obtained a 30% performance improvement in a servlet microbenchmark. |
Model Driven Architecture: How far have we come, how far can we go?Wednesday, 29 October – 15:30-17:00 |
Model Driven Architecture (MDA) is a technology that has been in the process of evolution for many years. Today, many vendors are now producing products that support MDA. We are hearing more and more success stories that indicate that this technology is the "real deal". But, with the failed promises of CASE in the late 1980's, many people still have questions about how much of an application can be generated from models and constraint languages. Is MDA really capable of generating enterprise applications? What are the technologies are available to implement MDA? Here is your opportunity to ask the experts the questions that are necessary to convince you of the validity of this new technology. Each of these panelists has been intricately involved in building the underlying foundations of Model Driven Architecture and its implementation.
Real-World ObjectsWednesday, 29 October – 15:30-17:00 |
15:30 - 16:00 |
Programming with Non-Heap Memory in RTSJGreg Bollella,
Sun Microsystems Laboratories
The Real-Time Specification for Java (RTSJ) provides facilities for deterministic, real-time execution in a language that is otherwise subject to variable latencies in memory allocation and garbage collection. In particular, RTSJ introduces two kinds of non-heap memory area (ScopedMemory and ImmortalMemory) and a kind of real-time thread (NoHeapRealtimeThread) that, together, can satisfy very demanding timeliness requirements because they run without interference from the garbage collector. What new RTSJ programmers quickly discover, though, is that the RTSJ "assignment rules"—governing references from one kind of memory to another—force designers to think more carefully about how data flows among the components of a system. In particular, for the hard real-time portions of a system, the normal Java practice of freely passing around references and letting the garbage collector recognize when an object is no longer needed simply doesn't apply. This report discusses two related design issues that all RTSJ users will face: how to explicitly manage non-heap memory and how to communicate information among components without violating RTSJ’s assignment rules. These issues are addressed from a practitioner’s viewpoint in the context of designing real-time control loops for driving and steering a 6-wheel Mars rover. The solution described here is termed “scoped memory scratchpads” and is believed to provide a good combination of Java-natural style and safety from programmer error. In this approach, transient data is allocated within a scoped memory area that is emptied later when all Runnables exeunt the memory area. Data that must be preserved across cyclic executions use memory pools, restricted so that all pool management is confined to a single component and is thus much easier to design and verify. Importantly, by maintaining a distinction between application-specific software and framework software, some of the details and discipline of using RTSJ can be hidden from application programmers. |
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16:00 - 16:30 |
The Parks PDA: A Handheld Device for Theme Park Guests in SqueakYoshiki Ohshima,
Twin Sun, Inc.,
Yoshiki.Ohshima@acm.org
The Parks PDA is a lightweight, handheld device for theme park guests that functions as a combination guidebook, map, and digital camera. Together with a small team of artists and designers, we created a prototype Parks PDA and content for a three hour guest experience, including a camera interface, a hyper-linked guide book, three games, an animal spotters guide, a cross-referenced map, animated movies with lip-synched sound, a ride reservation system, and more. Over 800 visitors to Disney's Animal Kingdom theme park tested the Parks PDA over a two week period. Developing the software for this test posed a number of challenges. The processor and memory of the target device were slow, the screen was small, and we had only three months of development time. We attacked these problems using Squeak, a highly-portable, open source Smalltalk implementation. We ported Squeak to the target device and used it to provide nearly bit-identical behavior across four different platforms. This supported a cross-platform development style that streamlined the production of both software and content. We created a tiny user interface and application framework for pen-based devices and implemented a simple card-stack media editor and player using it. We isolated and fixed several performance problems. The project was completed on time and guest response was favorable. Looking back, we can identify ten aspects of Squeak that contributed to the success of the project. While we feel that Squeak was the ideal tool for this job, many of the key benefits of Squeak could be enjoyed using other object-oriented languages such as Java J2ME or Python, especially if the source code of the virtual machine is available. |
The Biology of InformationWednesday, 29 October – 15:30-17:00 |
Walter Fontana is a research professor in residence at the Santa Fe Institute, has served as a Member of the Institute for Advanced Study in Princeton, NJ, with the Program in Theoretical Biology, and was a member of the University of Vienna faculty at the Institute for Theoretical Chemistry and Molecular Structural Biology.
OOPSLA Keynote - The Internet Paradigm ShiftThursday, 30 October – 8:30-10:00 |
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The computer industry has gone through a sea change in the past few years. The killer applications of the web era turned out not to be PC-based software packages like the web browser, but web hosted applications like google, mapquest and amazon.com. These applications are built on top of Linux and Apache, yet they are themselves fiercely proprietary. But what would most developers do with their source code? These massive systems are valuable for their data as much as for their programs. And by opening up XML web services APIs to that data, the most innovative of these sites are creating new opportunities for hackers to re-use that data and "scratch their own itch." What's more, as constantly updated services, these applications operate on very different timelines and processes than conventional software development. One of the greatest challenges for developers in the next few years is to understand and adapt to the paradigm shift implicit in network computing, and to shed the legacy thinking of the desktop era.
Speaker
Tim O'Reilly is founder and president of O'Reilly & Associates, thought by many to be the best computer book publisher in the world. In addition to publishing pioneering books like Ed Krol's The Whole Internet User's Guide & Catalog (selected by the New York Public Library as one of the most significant books of the twentieth century), O'Reilly has also been a pioneer in the popularization of the Internet. O'Reilly's Global Network Navigator site (GNN, which was sold to America Online in September 1995) was the first Web portal and the first true commercial site on the World Wide Web.
Tim has been an activist for internet standards and for Open Source software. He has led successful public relations campaigns on behalf of key internet technologies, helping to block Microsoft's 1996 limits on TCP/IP in NT Workstation, organizing the "summit" of key free software leaders where the term "Open Source" was first widely agreed upon, and, most recently, organizing a series of protests against frivolous software patents. Tim received Infoworld's Industry Achievement Award in 1998 for his advocacy on behalf of the Open Source community.
Garbage Collection 1Thursday, 30 October – 8:30-10:00 |
8:30 - 9:00 |
Mostly Concurrent Garbage Collection RevisitedKatherine Barabash,
IBM Haifa Research Laboratory,
kathy@il.ibm.com
The mostly concurrent garbage collection was presented in the seminal paper of Boehm et al. With the deployment of Java as a portable, secure and concurrent programming language, the mostly concurrent garbage collector turned out to be an excellent solution for Java's garbage collection task. The use of this collector is reported for several modern production Java Virtual Machines, and it has been investigated further in academia. In this paper, we present a modification of the mostly concurrent collector which improves the throughput, the memory footprint, and the cache behavior of the collector without foiling the other good qualities (such as short pauses and high scalability). We implemented our solution on the IBM production JVM and obtained a performance improvement of up to 22.8%, a reduction in the heap consumption by up to 13.6%, and no substantial change in the (short) pause times. The modified algorithm has subsequently been incorporated into the IBM production JVM. |
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9:00 - 9:30 |
An On-the-Fly Mark and Sweep Garbage Collector Based on Sliding ViewsHezi Azatchi,
Technion - Israel Institute of Technology,
hezia@cs.technion.ac.il
With concurrent and garbage collected languages like Java and C# becoming popular, the need for a suitable non-intrusive, efficient, and concurrent multiprocessor garbage collector has become acute. We propose a novel mark and sweep on-the-fly algorithm based on the sliding views mechanism of Levanoni and Petrank. We have implemented our collector on the Jikes Java Virtual Machine running on a Netfinity multiprocessor and compared it to the concurrent algorithm and to the stop-the-world collector supplied with Jikes JVM. The maximum pause time that we measured with our benchmarks over all runs was 2ms. In all runs, the pause times were smaller than those of the stop-the-world collector by two orders of magnitude and they were also always shorter than the pauses of the Jikes concurrent collector. Throughput measurements of the new garbage collector show that it outperforms the Jikes concurrent collector by up to 60%. As expected, the stop-the-world does better than the on-the-fly collectors with results showing about 10% difference. On top of being an effective mark and sweep on-the-fly collector standing on its own, our collector may also be used as a backup collector (collecting cyclic data structures) for the Levanoni-Petrank reference count |