Objects The Building Block

Jeff Magee and Jeff Kramer John Wiley and Sons, New York, NY, 1999, 374 pp. ISBN 0471987107, $64.99 The book is an introductory text to the ideas, concepts, and topics of concurrency. The text focuses on understanding concepts and techniques, and problems of concurrency, not on the implementation or language. The author's overall goal is that by a combination of learning and doing using Java should make the process of acquiring the skills relating to concurrency interesting, enjoyable, and challenging. The Java language is thus used only for illustration and programming experience of the reader. The book is intended for a computer science student or software developer. A background in programming is expected, as well as some familiarity with the essential concepts of object-oriented programming. Knowledge of the Java programming language and operating systems concepts is beneficial but not required. After reading the text, a reader can expect to have a broad understanding of the concepts of concurrency, the problems that arise, methods to emphasis desirable properties in a concurrent system, and ways to avoid the undesirable ones. The text provides a systematic treatment of concepts, as means to rigorously specify and model concurrent systems, with Java examples to animate and illustrate the concepts discussed. The book is organized into twelve chapters, with three appendices. The first eight chapters provide a concise and comprehensive foundation of concurrency, with the remaining four chapters focusing on more advanced concepts. The latter four chapters are somewhat supplemental and can be read at the discretion of the reader. The content of the text is self-contained, with no reliance upon external references. The authors provide a concluding set of notes and further topics which reference external works, but these are not used in the chapter contents. The introduction provides the foundation for the book, and an idea of what will follow in the rest of the text. The basics of modeling and Java are covered. Authors follow with the concepts of processes, threads and with the idea of concurrency. The emphasis is on using Java, and on the notation used to define a concurrent process or thread. The discussion continues covering interleaving and asynchronous concurrency. Various details about composition of parallel processes and finite state processing modeling are presented. The programming of concurrent execution using Java is then examined via the concept of multiple threads. Here, sharing objects among Java threads is also discussed. The concept of conditional synchronization is covered next, and is used to construct a monitor. The methods of the base object in Java is used, and a waiting queue associated with a Java object is discussed and implemented. This discussion is followed by introduction of deadlock. Authors show the conditions necessary for a deadlock to occur and present an analysis of a concurrent system establishing that such a system is deadlock-free. The classic Dining Philosopher's problem is used to illustrate the distinction between finding deadlocks in models and in programs. The presentation continues with the safety property (that asserts that nothing bad happens), and the liveliness property (that asserts that nothing good happens). Here, authors use the material on model-based design to consolidate many of the concepts previously discussed. No one modeling method or design methodology is emphasized. Then creation and elimination of threads in a running program is covered next. The dynamic starting and stopping of Java threads is presented. The discussion moves then to messaging passing. Asynchronous and synchronous messaging is presented with Java programming examples. The concept of a rendezvous, allowing for interaction in a messaging system, is also presented. Based on the concepts developed so far filter-pipeline, supervisor-worker, and announcer-listener concurrent architectures are examined. Java programs demonstrating how the elements of each model interact at runtime are developed. The presentation completes with modeling and implementing of timed systems. Time is signaled by the passage of successive time ticks. The authors then elaborate on a system that is event-based rather than thread-based. Java programs are used to illustrate in implementation the concepts discussed. The three appendices provide a reference, specification, and listing of semantics for the finite-state modeling algebra used by the authors throughout the book. The text is ideal for teaching in a classroom environment, or for a motivated reader to use for self-paced learning. Its organization follows a logical train of discussion and thought, with each chapter building successively on the other, with the more difficult concepts and topics withheld until later. This gradual approach makes the material flow smoothly and cohesively from the beginning to the end. The book is intended as a textbook, so does organize the material and discussion as one, but does not become too dry or bland to stifle the reader's interest in the material. The examples are inter-mixed with the discussion to highlight and emphasize essential points the authors make in each chapter. The text illustrates concepts well under discussion, and does not become a long-winded recital of theory. The topics examined are fundamental to concurrency, and are well illustrated and discussed, but no one topic is examined extensively. The code examples are well written concerning the programming style, indentation and comments. A CD is provided, containing the codes from the book. In addition supplementary material consisting of presentation slides and an errata is provided on the author's WWW site, as well as on the CD. The book is up to date both on the topics of concurrency, and with the Java applets, code, and programs used to illustrate them. Later, as the Java language evolves, the examples may need to be updated, but for the time being the text well represents that state of the Java language. William F. Gilreath, Micron Technology, Inc., Boise Idaho

The object-oriented theory has been widely used in software design and development and Java programming language is a popular object-oriented programming language for computer science related majors in higher education. With the huge demand for intelligent manufacturing employees in the work market, more and more universities have listed Java programming language in their curriculum for non-CS undergraduates. However, learning object-oriented programming languages, such as Java, is tough even for CS students. This paper presents how to improve non-CS undergraduate students’ learning outcomes of java language by adopting industry standard professional integrated development tool Eclipse and interactive visual educational tool BlueJ. Our Java programming language course is an alternative 8-week course including 16 h lecture and 16 h lab. Forty-seven junior students from mechanical engineering major were divided into two groups, 23 in the control group (CG) and 24 in the experimental group (EG). Students in both groups used Eclipse to write and run programs during the course while BlueJ was adopted to demonstrate the object-oriented concepts during the fifth and sixth weeks only for students in the EG. A pre-test, which was taken by students from both groups, shows no statistical differences in programming knowledge between the two groups. Results from the post-test at the end of the sixth week show students in EG achieved better performance than students in CG. Results of the survey for the EG reveal that students thought BlueJ was helpful for mastering the concepts of object-oriented programming.KeywordsJava programmingLearning outputHigher educationInteractiveVisualBlueJEclipse

The object of research in the article are the tools and capabilities of the C# programming language for the implementation of cybersecurity analysis software in local computer networks and computer-integrated systems. The relevance of the study is due to the importance of information security of computer and computer-integrated systems in government, military-industrial complex, private business etc., and due to the importance of training cybersecurity professionals in higher education to consider teaching examples in popular programming languages. The goal of the work is to research the possibilities of the C# programming language for the development of software that analyzes cybersecurity in local computer networks and computer-integrated systems. The tasks to be solved are: to develop software for scanning network device ports in computer networks and computer-integrated systems for information security audit, using tools and libraries of the C# programming language, to research the benefits and possibilities of using this programming language for this task. Research methods: theory of computer networks, object-oriented programming, theory of algorithms and data structures, theory of software testing. Conclusions. In this paper the possibilities and advantages of the C# programming language for developing cybersecurity analysis software for computer and computer-integrated systems were explored. In the course of work software that analyzes information security in local computer networks and computer-integrated systems was developed. This software can be used for educational purposes in learning the C# programming language and cybersecurity of computer systems. The developed software has the potential to be further improved and applied in various fields to test the cybersecurity of local computer networks and computer-integrated technologies.

The following paper essentially focuses on the innovative use of an open-source programming language, called ‘Processing’, in the architecture curriculum and the development of a line of teaching beginning with Processing and ending with object-oriented programming in Java. This represents one creative possibility through which students are able to overcome the typically difficult step of learning a programming language and simultaneously learn how to apply it as a design tool.

Computer programming language is the foundation of developing computer application technologies and software. C language and object-oriented programming language belong to commonly-utilized advanced computer languages, and they have certain relevance in logic. Meanwhile, they have their own advantages. In other words, C language and object-oriented programming language possess both relevance and differences in the aspects of selection and application. The work discussed the compiling essentials of C language and object-oriented programming language. Besides, the differences and applicability of those two languages in the aspect of programming were further analyzed.

This thesis proposes a novel way of performing type checking, whose results are incremental, depending on the provided local information. This new way of type checking is called co-contextual, where all context information of expressions, methods, classes, etc., is removed. Instead, we introduce corresponding structures using requirements. Standard type systems are translated to the co-contextual ones systematically using dualism as technique. Type systems play an important role to prevent execution errors from occurring during runtime. They are used to check programs statically for potential errors. Programs are type checked against a given set of rules. Depending on these rules programs are well-typed or not. The set of these rules is called typing rules. Each type rule associates types to the constructs of a program given a certain context. There can be different forms of contexts, depending on the features of the typed programming language. Functional languages use a typing context of variables and their types; object-oriented (OO) languages use additional class tables. Class tables are used for example to ensure that method and class declarations are well-typed. Type checking is performed top-down. While traversing the syntax tree of a program, typing contexts are extended with information on the expressions and their types. In case of OO, class tables are extended with clauses from class declarations, including the class members, i.e., fields, methods, or constructors. Contexts are passed through the nodes of the syntax tree in order to coordinate type checking between them. Therefore, while traversing the syntax tree top-down, the type checker creates dependencies between otherwise independent subexpressions. This way, it inhibits incrementalization and parallelization of type checking. That is, a change to a node of the syntax tree would require to redo the type check of the whole syntax tree. In this thesis a novel formulation of type systems is proposed, in order to remove dependencies between subexpressions. We propose a co-contextual formulation of typing rules that depends only on the local program constructs, e.g., expressions, methods, classes. The co-contextual typing rules have as conclusion a type and sets of requirements. That is, contexts and class tables are replaced by the dual concept of context and class table requirements. In addition, operations on contexts and class tables are replaced by new dual operations on requirements. The co-contextual type checker traverses a syntax tree bottom-up and merges context requirements of independently checked subexpressions. We describe a method for systematically constructing a co-contextual formulation of type rules from a regular context-based formulation and we show how co-contextual type rules give rise to incremental type checking. We derive co-contextual type checkers for functional and OO languages. As a representative of functional languages we consider PCF and extensions of it: records, parametric polymorphism, structural subtyping and let-polymorphism. Also, we investigate featherweight java (FJ) as the basis of OO languages and extensions of it: method overloading and generics. We build a1 co-contextual type checker for FJ enabling key features of OO languages: subtype polymorphism, nominal typing and implementation inheritance. The dualism between the co-contextual and contextual type systems preserves the correctness of the contextual calculus. That is, we prove the correctness of the co-contextual calculus via the equivalence between contextual type rules and their co-contextual formulations. We implemented an incremental type checker for PCF along with a performance evaluation showing that co-contextual type checking has performance comparable to standard context-based type checking, and incrementalization can improve performance significantly. Regarding FJ, we implemented a co-contextual type checker with incrementalization and compared its performance against javac on a number of realistic programs. Our performance evaluation shows significant speedups for the co-contextual type checker with incrementalization in comparison to javac.

Chapter 5 discusses some fundamentals of object-oriented programming languages (Section 5.1) and distributed programming languages (Section 5.4). It also specifically summarizes the major features of two object-oriented programming languages: c++ (Section 5.2) and SMALLTALK (Section 5.3), and one distributed programming language, namely, OCCAM and its predecessor CSP (Section 5.5). Although there are other object-oriented languages (e.g., ACTOR 1 and EFFEL 2 and distributed programming languages (see Section 5.4), these three languages are chosen to illustrate some basic ideas behind object-oriented programming and distributed programming. It is assumed that the reader is familiar with c.

Multiple dispatch uses the run time types of more than one argument to a method call to determine which method body to run. While several languages over the last 20 years have provided multiple dispatch, most object-oriented languages still support only single dispatch forcing programmers to implement multiple dispatch manually when required. This paper presents an empirical study of the use of multiple dispatch in practice, considering six languages that support multiple dispatch, and also investigating the potential for multiple dispatch in Java programs. We hope that this study will help programmers understand the uses and abuses of multiple dispatch; virtual machine implementors optimise multiple dispatch; and language designers to evaluate the choice of providing multiple dispatch in new programming languages.

Matthias Felleisen was awarded the 2011 SIGCSE Award for Outstanding Contribution to Computer Science Education for his and his research team's work on the TeachScheme! project, which was begun in 1995, and is now called by Design. This functions-first approach to teaching introductory programming and problem-solving features a robust software design methodology called the design recipe, and emphasizes good software engineering practices, such as early testing, from the beginning. These are combined with an integrated development environment (IDE), DrRacket, designed for beginners, featuring different language levels of the Scheme-like language, Racket, that combines simple syntax with customized error messages and support for graphics and animation accessible even for beginning programmers. The Program by Design project then includes support for transitioning to object-oriented programming in Java. However, many of this approach's concepts can be applied in different programming languages (such as Java, Python, or C++), or one can choose to start with this approach and then transition to different programming paradigms and/or languages at a pace appropriate to your situation.

MultiJava is a conservative extension of the Java programming language that adds symmetric multiple dispatch and open classes. Among other benefits, multiple dispatch provides a solution to the binary method problem. Open classes provide a solution to the extensibility problem of object-oriented programming languages, allowing the modular addition of both new types and new operations to an existing type hierarchy. This article illustrates and motivates the design of MultiJava and describes its modular static typechecking and modular compilation strategies. Although MultiJava extends Java, the key ideas of the language design are applicable to other object-oriented languages, such as C# and C++, and even, with some modifications, to functional languages such as ML.This article also discusses the variety of application domains in which MultiJava has been successfully used by others, including pervasive computing, graphical user interfaces, and compilers. MultiJava allows users to express desired programming idioms in a way that is declarative and supports static typechecking, in contrast to the tedious and type-unsafe workarounds required in Java. MultiJava also provides opportunities for new kinds of extensibility that are not easily available in Java.

Nowadays, when algorithms are combined with programming languages, great technological works are emerging. Examples of these works continue to differentiate and increase in military and police systems, agricultural applications, image processing applications, data engineering field, language processing works, and cyber security applications. With the differentiation of the areas of use of algorithms, the programming languages used on these platforms are also changing. Python is an object-oriented and functional modern programming language. It is ideal for beginners due to its readability and ease of use. C# is a simple, modern, object-oriented, and type-safe programming language that combines the high productivity of application development languages with the raw power of C and C++. The Java programming language, on the other hand, shares many features that are common to most programming languages used today. Since it is designed with the structures of C and C++, where their languages are similar, the language is familiar to C and C++ programmers (Lerdorf, 2002; Hejlsberg, 2003; Arnold, 2005; Deitel, 2004; Kelly, 2016; Gavrilović, 2018; Pala, 2019; Chollet, 2021; Chen, 2023).

Answer Set Programming (ASP) is a declarative programming paradigm which allows for easy modeling and solving of hard problems that are often cumbersome to implement in object-oriented programming languages. It was successfully applied to a range of applications from artificial intelligence, such as combinatorial or scheduling problems. On the other hand, real-world applications for end-users usually consist also of components which cannot be (easily) solved in ASP, such as user interaction via graphical user interfaces, presentation of results, and interfaces to data sources. Instead, realizing such components is typically in the domain of traditional (object-oriented) programming languages. To address this issue, we introduce a language which allows for a formal specification of the input and output of an ASP program, which can be exploited to easily interface the program from object-oriented languages using a dedicated library. While the language is independent from the concrete object-oriented language, we also provide and present a reference implementation as a Python library. We then discuss some applications which can be realized on top of our approach.

In the context of a Computer Science Major in Indonesian higher education, Java programming language is not only one of the most essential programming languages courses but is also considered to be challenging to learn. This fact has led to the development of numerous mobile learning (m-learning) applications to assist learners in acquiring Java programming skills independently. Most existing Java learning assistants are presented on websites or computer platforms which can only be accessed when students open their computer or Laptop and it mostly focuses on enhancing coding abilities, and practical hands-on. While these aspects are crucial, understanding the programming concepts and guided practice are equally essential in fundamental Java programming learning. This paper presents the concept of practical coding exercises in an m-learning application, providing a new interactive approach for learners as an alternative tool for learning Java programming so they can learn Java programming concepts more frequently from their smartphones. The primary objective is to investigate the feasibility of the proposed m-learning prototype. The proposed application is expected to offer intuitive coding exercises and case study opportunities. Experimental results demonstrate that the overall functionality of the proposed application is feasible for future implementation, with a usability score of 84.

A class dictionary defines all data structures that appear in a program as well as a language for describing data specified by the data structures. We demonstrate that class dictionaries are ideal for simplifying object-oriented programming. Our class dictionary-based approach to object-oriented programming is independent of any particular programming language, so it is applicable to a large variety of object-oriented systems. The experience in designing and using over one hundred class dictionaries has resulted in a set of useful design techniques. This novel approach to object-oriented programming makes interesting links between language design, data structure design, and data-base design.

The emergence of Unified Modeling Language (UML) as a standard for modeling systems has encouraged the use of automated software tools that facilitate the development process from analysis through coding. The UML state machine diagram is used for modeling the dynamic aspects of systems and includes many concepts that are not present in most popular programming languages, like Java or C++. There exists a gap between high level modeling language and a programming language. This paper proposes an approach to narrow the gap between multiple UML models and an implemented system. The narrowing of gap is achieved by generating compact and efficient Java code directly from UML state machine having sequential and concurrent substates. The code generation is achieved by creating a mapping between UML behavior and the Java programming language. Our model can work as a basis for automatic code generation for object-oriented systems.