Java Examples Research Articles

Processes, Systems & Tests: Defining Contextual Equivalences

In this position paper, we would like to offer and defend a new template to study equivalences between programs -- in the particular framework of process algebras for concurrent computation.We believe that our layered model of development will clarify the distinction that is too often left implicit between the tasks and duties of the programmer and of the tester. It will also enlighten pre-existing issues that have been running across process algebras as diverse as the calculus of communicating systems, the $\pi$-calculus -- also in its distributed version -- or mobile ambients.Our distinction starts by subdividing the notion of process itself in three conceptually separated entities, that we call \emph{Processes}, \emph{Systems} and \emph{Tests}. While the role of what can be observed and the subtleties in the definitions of congruences have been intensively studied, the fact that \emph{not every process can be tested}, and that \emph{the tester should have access to a different set of tools than the programmer} is curiously left out, or at least not often formally discussed.We argue that this blind spot comes from the under-specification of contexts -- environments in which comparisons takes place -- that play multiple distinct roles but supposedly always \enquote{stay the same}.We illustrate our statement with a simple Java example, the \enquote{usual} concurrent languages, but also back it up with $\lambda$-calculus and existing implementations of concurrent languages as well.

Performance analysis of languages working on Java Virtual Machine based on Java, Scala and Kotlin

This article presents the results of a literature study related to the construction and operation of Java Virtual Machine, as well as performance tests of selected languages using the aforementioned runtime environment on the example of Java, Scala and Kotlin. Performance testing was carried out using two applications built using the Apache Maven archetype with the built-in Java Microbenchmark Harness library.

Using Augmented Reality in Remote Laboratories

This paper introduces the concept of “augmented reality” as a novel way to enhance visualization in remote laboratories for engineering education. In a typical remote experimentation session, students get access to a remote real plant located at the laboratory to carry out their assignments. Usually, the graphical user interface allows users to watch the equipment by video stream in live. However, in some cases, visual feedback by video stream could be enhanced by means of augmented reality techniques, which mix together in one image, the video stream and computer generated data. Such mixture produces an added value to remote experimentation, increasing the sense of presence and reality, and helping to understand much better the concepts under study. In this work, a Java-based approach to be used in the remote experimentation context for pedagogical purposes is presented. Firstly, a pure Java example is given to readers (including the source code) and then, a more sophisticated example using a Java-based open source tool known as Easy Java Simulations is introduced. This latter option takes advantage of a new developed component, called camimage, which is an easy-to-use visual element that allows authors to capture video stream from IP cameras in order to mix real images with computer generated graphics.

Localized Surface Disruptions Observed by InSAR during Strong Earthquakes in Java and Hawai'i

Abstract Interferometric Synthetic Aperture Radar data spanning strong earthquakes on the islands of Java and Hawai‘i in 2006 reveal patches of subsidence and incoherence indicative of localized ground failure. Interferograms spanning the 26 May 2006 Java earthquake suggest an area of about 7.5 km 2 of subsidence (∼2 cm) and incoherence south of the city of Yogyakarta that correlates with significant damage to housing, high modeled peak ground accelerations, and poorly consolidated geologic deposits. The subsidence and incoherence is inferred to be a result of intense shaking and/or damage. At least five subsidence patches on the west side of the Island of Hawai‘i, ranging 0.3–2.2 km 2 in area and 3–8 cm in magnitude, occurred as a result of a pair of strong earthquakes on 15 October 2006. Although no felt reports or seismic data are available from the areas in Hawai‘i, the Java example suggests that the subsidence patches indicate areas of amplified earthquake shaking. Surprisingly, all subsidence areas in Hawai‘i were limited to recent, and supposedly stable, lava flows and may reflect geological conditions not detectable at the surface. In addition, two ‘a‘ā lava flows in Hawai‘i were partially incoherent in interferograms spanning the earthquakes, indicating surface disruption as a result of the earthquake shaking. Coearthquake incoherence of rubbly deposits, like ‘a‘ā flows, should be explored as a potential indicator of earthquake intensity and past strong seismic activity.

Interactive embedded examples

A demonstration of the integration of a program animation tool into a set of web based notes used by instructors for lecturing and students for studying. Standard, conventionally prepared C++ and Java examples are dynamically incorporated into the class notes and can be interactively run in the animation tool directly from within the notes.

Concurrent and distributed computing in Java

Concurrent and Distributed Computing in Java addresses fundamental concepts in concurrent computing with Java examples. The book consists of two parts. The first part deals with techniques for programming in shared-memory based systems. The book covers concepts in Java such as threads, synchronized methods, waits, and notify to expose students to basic concepts for multi-threaded programming. It also includes algorithms for mutual exclusion, consensus, atomic objects, and wait-free data structures. The second part of the book deals with programming in a message-passing system. This part covers resource allocation problems, logical clocks, global property detection, leader election, message ordering, agreement algorithms, checkpointing, and message logging. Primarily a textbook for upper-level undergraduates and graduate students, this thorough treatment will also be of interest to professional programmers.

Operating system scenarios as Use Case Maps

This paper summarizes the analysis, design, implementation, and performance analysis of an object-oriented operating system. The analysis applies Use Case Maps (UCMs) to provide a high-level abstraction of the behavior scenarios for state transition, character output, network access, and disk access. The UCM for state transitions is converted into a queueing network for simulation study of I/O-bound versus CPU-bound systems. An overview of the later stages emphasizes UML for architecture and detailed collaboration, as well as Java examples. The performance of the disk sub-system is analyzed by instrumenting the Java code, and the results show that design choices can affect the throughput.

Java기반의 MPEG-4 시스템 구현

본 논문에서는 무선 랜 기반의 유무선 통합서비스 사업을 위해 동영상 멀티미디어 컨텐츠를 포함한 멀티미디어 메시징 서비스를 제공하기 위해 자바와 자바 3차원 기반의 MPEG-4 표준 규약에 충실한 MPEG-4 시스템 구현에 관한 것이며, 이를 위해 MPEG-4 시스템 구현에 필요한 기술, 유무선 통합 멀티미디어 서비스의 정의, DMIF 구현 및 mp4 파일 파싱 등의 구체적인 MPEG-4 시스템 구현 방법 등을 기술한다. In this paper, an implementation example of Java based MPEG-4 system that follows MPEG-4 standard protocols in order to provide multimedia-messaging service is introduced. The multimedia-messaging service is a wireless LAN based wired and wireless service that delivers multimedia contents including video and audio information. Detailed Methods to develop a MPEG-4 system like technology of MPEG-4 system implementation, definition for wired and wireless multimedia service, DMIF implementation, and mp4 file Parsing are described.

Using an APL approach with Java

Three Java examples are developed to advance an APL approach in reducing conceptual intricacies in Java programming. The key part of these examples is a new Java class named APL. By making an instance of this class, a programmer is in a position to call appropriate APL primitive functions and operators to process data. In other words, a programmer is able to think in terms of arrays while programming in Java. All sample code is written in Java. The goal is to eventually implement all APL primitive functions and operators in this new APL class following the Linux paradigm of contributions from many authors.

Concurrency State Models and Java Programs

Concurrency State Models and Java Programs

A comparison of the concurrency features of Ada 95 and Java

subclasses of an abstract class need to provide implementations for any abstract methods that they inherit. A variable declared of a particular class is intrinsically polymorphic: it can designate objects from that class or from any of its direct or indirect subclasses. Objects are generated on the heap from invocations of constructors. Complementing the class concept is the feature known as an interface. An interface may be viewed as a restricted form of class with no “implementation” aspects. Thus the only methods allowed in an interface are abstract methods, and the only variables allowed in an interface are so-called final variables, which are constants. A class is allowed to extend only one class but may implement an arbitrary number of interfaces; in this sense Java provides some support for multiple inheritance. Here is an example of Java’s main OOP concepts, adapted from [4]: public class Point{ protected static int numPts=0; protected int x, y; public Point(int x, int y){ this.x=x; this.y=y; numPts++; } public static int getNumPts(){ return numPts; } public void shift(int ∆x, int ∆y){ x += ∆x; // Note Unicode character

The Caubhikas and the Indian Drama

An interesting attempt has been made by Professor H. Lüders to vindicate for the shadow play an important place in the development of the Indian drama. The term denoting the performers of such plays he holds to have been Çaubhika, or, in vernacular form, sobhiya; they explained to the audience the shadow pictures displayed before them, and thus were precursors of the true drama. The example of Java is called into service to meet the obvious criticism that every consideration tells in favour of the view that the shadow play is later than, and based upon, the true drama.