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关于java英文参考文献

关于java英文参考文献Java, a versatile programming language, has been a cornerstone of software development since its inception in the mid-1990s. Its object-oriented nature and platform independence make it a popular choice for developers worldwide.The language's extensive ecosystem is well-documented in numerous scholarly articles and books, offering insights into its design principles and practical applications. For beginners, "Head First Java" by Kathy Sierra and Bert Batesis a recommended starting point, blending engaging narratives with technical explanations.As one progresses, "Effective Java" by Joshua Bloch provides a more in-depth look at the language's best practices, catering to intermediate and advanced programmers. It covers topics such as exception handling and concurrency, which are crucial for writing robust Java applications.For a comprehensive understanding of Java's underlying mechanisms, "Java Concurrency in Practice" by Brian Goetz et al. is an invaluable resource. It delves into the complexities of multi-threading, a critical aspect of modern software development.When exploring Java's integration with web technologies, "Java Web Services" by William C. Crawford provides a clearguide to building and consuming web services, a common requirement in today's interconnected applications.Lastly, for those interested in the broader implications of Java in enterprise environments, "Enterprise Integration Patterns" by Gregor Hohpe and Bobby Woolf offers a collection of design patterns that facilitate the building ofdistributed systems.These references not only serve as educational tools but also as a testament to the enduring influence of Java in the field of computer science.。

java英文参考文献(20210507015628)

java 英文参考文献篇一：外文参考文献译文及原文本科毕业设计（论文）外文参考文献译文及原文学院_________ 计算机学院专业___计算机科学与技术_年级班别___ 2009级（1）班学号学生姓名______ ________指导教师_____ ________2013年5月目录译文： (1)第一章微软.NET 平台的介绍 (3)1.1 简介.................................................................................................................1.1.1 .NET 平台简介 (3)1.1.2 微软的.NET 和WINDOWS 的基3因 (4)1.1.3 微软.NET 体系结构 (4)1.1.4 .NET 平台的特点 (4)J \\\ ................................................................................................................................................................................................................................................................................................................................ ■1.1.5 多国语言的发展 (5)1.1.6 平台和处理器独立性 (6)1.1.7 自动内存管理 (7)1.1.8 支持的版本 (7)1.1.9 支持的开放标准 (8)1.1.10 配置简单 (8)1.1.11 分布式体系结构 (9)1.1.12 与非托管代码的互用 (9)原文：Foreword ..................................................................................................... .............................. 11 Chapter1 Introduction of the Microsoft .NET Platform 131.1 Introduction ................................................................................................. .. (13)1.1.1 Introduction of the .NET Platform (13)1.1.2 Microsoft .NET and WindowsDNA (15)1.1.3 Microsoft .NET Architecture Hierarchy ....................................151.1.4 Features of the .NET Platform (16)1.1.5 Multilanguage Development (17)1.1.6 Platform and Processor Independence (18)1.1.7 Automatic Memory Management (19)1.1.8 Versioning Support (20)1.1.9 Support for OpenStandards (21)1.1.10 Easy Deployment (22)1.1.11 Distributed Architecture (23)1.1.12 Interoperability with Unmanaged Code (23)译文：、尸■、亠前言在电脑软件的历史上，很少有一种技术能够得到开发者和业界如此强烈的正面响应。

使用java开发连连看游戏后毕业设计外文文献及翻译[管理资料]

毕业设计说明书英文文献及中文翻译班级：学号：姓名：学专指导教师：The Java 2 user interfaceGraphical and user interface capabilities have progressed in leaps and bounds since the early days of the Java language. The Java 2 platform contains a sophisticated cross-platform user interface architecture that consists of numerous high-level components, an advanced feature-rich device-independent graphics system, and a host of multimedia extensions. In this article, we'll explore this progression, examine the capabilities of the current version in detail, and finish by looking to the future to see what release will offer.Prior to the release of the Java 2 platform, the Abstract Window Toolkit (AWT) was the extent of the Java platform's graphical capabilities. Various technologies, such as Swing, were introduced as optional extensions. With the Java 2 platform, most of these extensions have found their way into the core as part of the Java Foundation Classes (JFC). JFC refers to the entire set of graphical and user interface technologies included in the Java 2 platform, including AWT and Swing. In this article, we'll explore each of the major components of the JFC and then discuss some of the optional extensions.The heart of the JFC: SwingSwing, a GUI toolkit with a rich set of components, forms the heart of the JFC's user interface capabilities. It is both a replacement for the components the AWT provides and also a big step forward.When integration was the priorityIn the first releases of the JDK, integration with the native platform was considered a priority and so the AWT provided components that were implemented using the native components of each platform (in the Java programming vernacular, these are now known as heavyweight components). For example, on UNIX platforms the class was implemented with a Motif PushButton widget.The same Java application had a different appearance on each platform, but the intention was that the different implementations were functionally equivalent. Of course, this is where the problems start. For simple interfaces, the equivalence is true, but the model breaks down as complexity increases simply because the componentsare different, and they will always behave slightly differently in some situations no matter how many bugs are fixed and how many times parts of the AWT are rewritten.The other problem that cropped up by placing a priority on integration was functionality. The AWT provided only a limited set of components because of the "lowest common denominator" approach -- a particular component or function can only be provided if it is available on every platform. A classic example is mouse buttons. Back in JDK , there was no way to distinguish between mouse button presses because the Macintosh had only one mouse button, and so every other platform had to behave as if it too supported only one mouse button.As the language became more of a platform in its own right, the approach to GUIs moved toward identical appearance and behavior across all platforms. To achieve this goal, the native components have to be abandoned as much as possible. But, clearly, some native code is still required. You can't make a window appear on UNIX without X System Window calls being involved.Enter Swing, which achieved this goal by making use of a subset of the AWT, including the basic drawing operations and the certain classes in the package: Container, Window, Panel, Dialog, and Frame.Best of all possible approachesSwing does not completely follow the "Java language as a platform" route. Instead, it combines the best of both approaches by offering a bridge back to the native platforms.The mechanism for establishing this bridge is referred to as PluggableLook-and-Feels (which is pretty close to the concept of themes, popular in the Linux community). Each Swing component has a model of its functionality and a separate appearance (the look-and-feel), which can be set in advance or changed on the fly.Swing provides a Java look-and-feel (previously known as Metal), separate ones for the Windows and Motif platforms, and one for the Macintosh platform (as an extra option). The platform look-and-feels don't use the native components of the platform like the AWT does. Instead, they use lightweight components that are drawn to have the same appearance as the native components. This is good for functionality, butthere are always some differences in look or behavior, so complex interfaces will never be identical to ones that use native components.Furthermore, you can roll your own look-and-feel, which is a great ability to have when crafting one for highly specialized applications or when providing a corporate look-and-feel across a range of applications.Platform-independent drag and dropJDK added a general mechanism, found in the package, that enabled the transferring of data between and within applications, as well as the ability to manipulate the system clipboard.The package was introduced in the Java 2 version. This package builds on the data-transfer mechanism by providing drag-and-drop facilities that can operate in a platform-independent manner within a single Java application or between two Java applications. It can also behave in a platform-dependent manner in order to integrate with the drag-and-drop facilities of the native platform.The Drag and Drop (DND) API is quite challenging to use because it operates at a high level of abstraction to support the different ways in which it can work and because it is designed to operate on arbitrary datatypes, as specified by the interface. Let's take a look at an example.Enabling the disabled: AccessibilityThe JFC Accessibility API equips Java applications so they can be accessed by users of all abilities, including people with sight-, hearing-, or dexterity-related difficulties. These might include the inability to discern visible or auditory cues or to operate a pointing device.Two of the most important features of accessibility support are screen readers and magnifiers. Screen readers allow users to interact with a GUI by creating anoff-screen representation of the interface and passing this to a speech synthesizer or a Braille terminal. Screen magnifiers provide an enlarged window of the screen, typically from 2 to 16 times the normal size. They generally keep track of pointer movements and changes in input focus and adjust the enlarged view accordingly. In addition, techniques such as font smoothing may be used to create a clearer picture. The Java Accessibility BridgeSome host systems, such as Microsoft Windows, provide their own accessibility features. By default, Java applications do not fully support them. For example, with native applications the screen magnifier detects when the input focus is switched to a different user interface component, such as by using the Tab key, and it adjusts the portion of the screen that is being magnified to show the component that now has the input focus.However, Swing applications use lightweight components, which are treated as images by the operating system, instead of discrete components. This means the screen magnifier cannot track changes in input focus in the same way as with native applications.This is exactly the problem the Java Accessibility Bridge for Windows solves. It creates a map between events relating to lightweight components and native system events. By using the Bridge, Java applications that support the Accessibility API are then fully integrated with the Windows accessibility support.From primitive to advanced: Java 2DBefore the Java 2 platform, graphical capabilities in the language were rather primitive, limited to solid lines of single-pixel thickness; a few geometric shapes such as ovals, arcs, and polygons; and basic image-drawing functionality. All that changed with the introduction of the Java 2D API, which contains a substantial feature set.The core of this API is provided by the class, which is a subclass of . The remainder of the API is provided by other packages within the hierarchy, including , , and .The classThis class is a subclass of , the class that provided graphical capabilities prior to the Java 2 release. The reason for this arrangement: backwards compatibility. Components are still rendered by calling their paint() method, which takes a Graphics object.In the current version of the language, though, the object is really a Graphics2D object. This means that a paint() method can either use the Graphics object as a Graphics object (using the old drawing methods) or cast it to a Graphics2D object. Ifit uses the second option, then any of the additional capabilities of the 2D API can be used.The packageThe package provides a number of classes relating to two-dimensional geometry, such as Arc2D, Line2D, Rectangle2D, Ellipse2D, and CubicCurve2D. Each of these is an abstract class, complete with two non-abstract inner classes called Double and Float (which are subclasses of the abstract outer class).These classes allow the various geometric shapes to be constructed with coordinates of either double or float precision. For example, (x,y,w,h) will construct an ellipse bounded by a rectangle of width w and height h, at position (x,y), in which x, y, w, and h are all floating-point values.Also in this package is the AffineTransform class, which forms a core element of the 2D API. An affine transformation is one in which parallel lines remain parallel after the transformation. Examples of this type of transformation include such actions as translation, rotation, scaling, shearing, or any combination of these. Each transformation can be represented by a 3x3 matrix that specifies the mapping between source and destination points for the transformation.Instances of the AffineTransform class can be created directly from a matrix of floating-point values, although they are more usually created by specifying one or more translation, rotation, scaling, or shearing operations. Mostly double-precision values are used, and angles are measured in radians (not degrees as used by the Arc2D class).Text renderingThe text capabilities of the Java 2D API are impressive. They include:Anti-aliasing and hinting for improved output qualityThe ability to use all the system-installed fontsThe ability to apply the same operations (rotation, scaling, painting, clipping, and so on) to text as to graphic objectsSupport for adding embedded attributes to strings (such as font, size, weight, and even images)Support for bi-directional text (to enable right-to-left character runs like you would encounter in Arabic and Hebrew)Primary and secondary cursors that can navigate through text containing both right-to-left and left-to-right character runsAdvanced font-measurement capabilities, surpassing those of the old classLayout capabilities to word-wrap and justify multi-line textMultimedia options: Java Media APIsThe Java Media APIs are a set of resources covering an extensive range of multimedia technologies. Some of them, such as the 2D and sound APIs, are part of the core J2SE platform; the rest are currently optional extensions, but some of them will no doubt find their way into the core in the future. The other APIs in this area are Java 3D, Advanced Imaging, Image I/O, the Java Media Framework (JMF), and Speech.Java 3DThe Java 3D API provides a set of object-oriented interfaces that support a simple, high-level programming model, enabling developers to build, render, and control the behavior of 3D objects and visual environments.The API includes a detailed specification document and implementation for packages and .Advanced ImagingOperations covered by this specification enhance a user's ability to manipulate images. It includes such operations as contrast enhancement, cropping, scaling, geometric warping, and frequency domain processing.This type of functionality is applicable to various fields, such as astronomy, medical imaging, scientific visualization, meteorology, and photography.Image I/OThis API defines a pluggable framework for reading and writing images of various formats. This new API is being designed through the Java Community Process.Java Media Framework (JMF)The JMF is an API for incorporating audio, video, and other time-based media into Java applications and applets. This optional package extends the multimedia capabilities of the J2SE platform.SpeechThe Java Speech API allows developers to incorporate speech technology into user interfaces for Java applets and applications. The API specifies a cross-platform interface to support command-and-control recognizers, dictation systems, and speech synthesizers.This blanket API is divided into several specifications:Java Speech API Specification (JSAPI)Java Speech API Programmer's GuideJava Speech API Grammar Format Specification (JSGF)Java Speech API Markup Language Specification (JSML)There is no Sun reference implementation for this API, but there are numerous third-party implementations, including Speech for Java (available from IBM alphaWorks), which uses ViaVoice to support voice-command recognition, dictation, and text-to-speech synthesis.Java 2 用户界面自从Java语言出现的早期到现在，图形和用户界面功能已取得了飞跃式的发展。

Java、J2ee的Spring框架和大数据技术外文文献翻译

文献信息文献标题：Implementing and Analyzing Big Data Techniques with Spring Frame Work in Java & J2EE Based Application（基于Java/J2EE的Spring 框架实现和分析大数据技术）文献作者及出处：Saxena A, Kaushik N, Kaushik N. Implementing and Analyzing Big Data Techniques with Spring Frame Work in Java & J2EE Based Application[C]//Proceedings of the Second International Conference on Information and Communication Technology for Competitive Strategies. ACM, 2016:5.字数统计：英文2814单词，15570字符；中文4912汉字外文文献Implementing and Analyzing Big Data Techniques withSpring Frame Work in Java & J2EE Based ApplicationAbstract –In the time of big data techniques with spring framework on java, web servers or application server as the significant channel in big data should be updated to meet execution and force imperatives. Significant endeavors have been put resources into web server or application server conveyance and web storing procedures, but very few efforts have been paid to improve hardware-favored web type services. Big Data with spring framework in java is a promising business and computing model in web framework. Spring is the most popular open source Java application Framework. It combines all the industry-standard frameworks (for e.g. Struts and Hibernate) and approaches into one bundle. The expense and working costs of data centers have skyrocketed with the increase in computing capacity. Big data is a concept that defines the large volume of both structured and unstructured data – that inundates a business on a day-to-day environment. This research argues the need to provide novel method and tools to bolster programming engineers meaning toenhance vitality productivity and minimize the subsequent from outlining, creating, sending and running programming in Big Data with spring framework.Keywords –Java, J2ee, Hadoop Framework, spring, Big Data.I.INTRODUCTIONBig Data with spring framework based applications and innovation components are composed in java& J2ee. Java has inherent limitations that can keep endeavors from advancing execution and using vast in memory data sets. Organizations endeavor to work around these dormancy, versatility and memory size issues by utilizing separate caching frameworks or analyzing a subset of accessible data. Then again, this influences the quality and convenience of business choices and even lessens revenue.Objective of big data:•By giving a semantic end-to-end connection between clients and data sources.•Enabling clients to quickly define instinctive queries utilizing natural vocabularies and conceptualizations.•Seamlessly coordinating information spread over various distributed data sources, including streaming sources.•Exploiting gigantic parallelism for adaptability a long ways past traditional RDBMSs and along these lines lessening the turnaround time for information requests to minutes as opposed.Objectives for Spring Framework:•The potential favorable circumstances of utilizing Spring's dependency injection.•Dependency injection in XML, utilizing constructor.•Default scope for Spring beans.•How to declare an initialization method in a Spring bean.Java:Java is one of the most robust, mainly used and perfect programming languagefor creating enterprise applications. Over the years, Java development has evolved from applets run on a web browser (chrome, mozila) to large enterprise distributed applications run on multiple servers. Presently, Java has three different flavors, and each addresses certain programming requirements.Spring framework is the most well known application advancement structure for big business Java. A great many designers around the globe use Spring Framework to make high performing, effortlessly testable, reusable code.J2ee:J2ee utilizes a multi-level circulated application model. There are three levels in the commonplace J2EE application model: presentation tier, business logic tier and data tier.Framework:The framework is intended to streamline the full improvement cycle, from building, to sending, to looking after applications. it can be considered as an arrangement of capacities helping the designers in making the applications.II.Spring FrameworkSpring is a lightweight framework. It can be considered as a structure of systems in light of the fact that it gives backing to different structures, for example, Struts, Hibernate, Tapestry, EJB, JSF and so forth. The system, in more extensive sense, can be characterized as a structure where we discover arrangement of the different specialized issues.Features of SpringFramework:•Lightweight -Spring is lightweight as far as size and overhead. The whole spring system can be conveyed in a Jar file that weighs in at a little more than 1 MB.•Aspect-Oriented - Spring supports the features of aspect oriented programming approach that enables cohesive development.•Container -Spring is a compartment in light of the fact that it deals with the life cycle and configuration of application objects.•Framework -Spring accompanies MVC web application framework, based on core Spring functionality. This structure is profoundly configurable by means of methodology interfaces, and obliges various perspective innovations like JSP, Speed, Tiles.Aspect oriented programming:To permit clients to actualize custom perspectives, supplementing their utilization of OOP with AOP. Aspect oriented programming is regularly characterized as a programming strategy that advances partition of worries inside of a software framework. Frameworks are made out of a few parts, each in charge of a particular bit of usefulness.AOP gives you perspectives. Aspects empower modularization of concerns, for example, transaction management that cut across multiple types and objects.AOP is utilized as a part of theSpring Framework:•To give definitivedeclarative enterprise services, particularly as a substitution for EJB explanatory services. The most critical such service is explanatory transaction management.•To permit clients to actualize custom aspects, complementing their utilization of OOP with AOP.Inversion of Control:The IoC (Inversion of Control) pattern utilizes three diverse methodologies as a part of request to accomplish decoupling of control of services from your components:•Interface Injection : Your components expressly fit in with an arrangement of interfaces, with related setup metadata, keeping in mind the end goal to permit the system to oversee them accurately.•Setter Injection : External metadata is utilized to arrange how your segments can be cooperated with.•Constructor Injection: Your components are enrolled with the framework, including the parameters to be utilized when thecomponents are developed, and the structure gives instances of the component with the majority of the predeterminedfacilities applied.Dependency Injection:Dependency Injection (DI) is a design pattern that expels the dependency from the programming code with the goal that it can be anything but difficult to oversee and test the application. Dependency Injection makes our programming code inexactly coupled.III.Big DataBig Data is more and various types of data than is effectively taken care of traditional relational database management systems (RDBMSs). Another helpful point of view is to describe big data as having high volume, high speed, and high assortment.•High volume: the sum or amount of data.•High speed: the rate at which data is created.•High assortment: the distinctive sorts of data.Big Data is a technique that is utilized to portray data that is high volume and speed,requires new technologies and systems to catch, store, and analyze it; and is utilized to upgrade decision making, give understanding and disclosure, and bolster and advance technique. Normally, to analyze data, individuals used to make diverse data sets in view of one or more regular fields so examination turns out to be simple. Big data has numerous sources. For instance, each mouse event on a site can be caught in Web log files and examined keeping in mind the end goal to better comprehend customers' purchasing practices and to impact their shopping by powerfully suggesting products. Social media sources, for example, Facebook and Twitter create enormous measures of remarks and tweets. This data can be caught and broke down to comprehend, for instance, what individuals consider new item presentations. Machines, for example, savvy meters, produce data. These meters persistently stream information about power, water, or gas utilization that can be imparted to clients and consolidated with estimating arrangements to rouse clients to move some of their vitality utilization.Figure 1. Information flow of Big DataThis Figure 1shows different phases of Big Data Uses of Big Data.1.Fraud detection:In many cases, fraud is discovered long after the fact, and soon thereafter the harm has been done and all that is left is to minimize the harm and modify arrangements to keep it from happening once more. Big Data stages that can examine cases and exchanges continuously, recognizing huge scale designs crosswise over numerous exchanges or identifying abnormal conduct from an individual client, can change the fraud detection game.2.IT log analytics:IT arrangements and IT divisions create a colossal amount of logs and follow information. Without a Big Data arrangement, quite a bit of this information must go unexamined.3.Call center analyticsBig Data arrangements can distinguish repeating issues or client and staff conduct designs on the fly not just by comprehending time/quality determination measurements, additionally by catching and preparing call content itself.4.Social media analysisEveryone and their moms are on online networking nowadays, whether they're"preferring" organization pages on Facebook or tweeting protestations about items on Twitter. A Big Data arrangement fabricated to reap and analyze online networking movement, similar to IBM's Cognos Consumer Insights, a point arrangement running on IBM's BigInsights Big Data stage, can comprehend the jabber. Social mediacan give continuous experiences into how the business sector is reacting to items and battles. With those bits of knowledge, organizations can change their valuing, advancement, and battle arrangement on the fly for ideal results.Figure 2. Application area of Big DataCase of Big Data in Real world:•Consumer item organizations and retail associations are checking online networking like Facebook and Twitter to get an uncommon perspective into client conduct, inclinations, and item observation.•Manufacturers are observing moment vibration information from their hardware, which changes somewhat as it wears out, to foresee the ideal time to supplant or keep up.•Manufacturers are likewise observing informal organizations, however with an alternate objective than advertisers: They are utilizing it to identify reseller's exchangebolster issues before a guarantee disappointment turns out to be openly adverse.•The government is making information open at both the national, state, and city level for clients to grow new applications that can produce open great.•Financial Services associations are utilizing information mined from client connections to cut up their clients into finely tuned fragments.•Advertising and showcasing offices are following online networking to comprehend responsiveness to campaigns, advancements, and other promoting mediums.•Insurance organizations are utilizing Big Data investigation to see which home protection applications can be instantly prepared, and which ones need an approving in-individual visit from an operators.•By grasping social media, retail associations are drawing in brand promoters, changing the impression of brand rivals, and not with standing empowering eager clients to offer their items.•Hospitals are investigating medicinal information and patient records to predict those patients that are prone to look for readmission inside of a couple of months of release. The doctor's facility can then mediate with expectations of anticipating another expensive doctor's facility sit tight.•Web-based organizations are creating data items that consolidate information assembled from clients to offer additionally engaging proposals and more fruitful coupon programs.•Sports groups are utilizing information for following ticket deals and even for tracking team strategies.Figure 3. Architecture of Big DataThis figure 3 first extracts the social, archive, service data some part of operational data then transforms with new techniques then load in to server and finally Big Data analytic with latest technique.Figure 4. stages of Big DataThis figure 4 divides the data in to three stages.1.Data Acquisition form:this stage of data cover with streams, internet data, cloud data source, mobile data source, desktop data source and server data source.2.Data refining and processing form:this stage covers refining and processing the data of corporate Hub. Corporate data hub is combination of refining workloads and local workloads.3.Data Shipping form:this stage of architecture extract the data from different sources.IV.HADOOP ARCHITECTURESpring for Apache Hadoop streamlines providing so as to create Apache Hadoopa brought together design model and simple to utilize APIs for utilizing HDFS, MapReduce, Pig, and Hive. It likewise furnishes coordination with other Spring eco –system venture, for example, Spring Incorporation and Spring Cluster empowering you to create answers for enormous information ingest/fare and Hadoop work process organization.Apache Hadoop is a software patternfor preparing a lot of information over conceivably greatly parallel groups of servers. The key segment of Hadoop is the Hadoop Distributed File System,which deals with the data shared over the different servers. It is a direct result of HDFS that such a variety of servers can be overseen in parallel. HDFS is file based and does not require any data model to save and process data. It can store data of any structure, however is not a RDBMS. HDFS can deal with the capacity and access of an Web logs, XML documents type of data and the length of the data can be placed in a file and replicated into HDFS. The Hadoop base regularly runs MapReduce programs in parallel. MapReduce takes substantial datasets, extricates and changes valuable data, conveys the data to the different servers where handling happens, and amasses the outcomes into a smaller,easier-to-examine file. It doesn't perform analytics fundamentally; rather, it gives the system that controls the projects that perform the analytics. As of now, jobs can be run just a in batch, which restrains the utilization of Hadoop/MapReduce for real-time applications. In spite of the fact that Hadoop and MapReduce are talked about and regularly utilized together, they can be utilized independently. That is, Hadoop can be utilized without MapReduce and the other way around.Figure 5 outlines how process is carried out by using Hadoop/MapReduce. This is a basic process that should likewise be possible with SQL based query and a RDBMS, yet gives a decent sample of Hadoop/MapReduce handling. At the left is an information document with records containing Deer, Bear , River, and Car. The goal is to tally the quantity of times every word happens. The initial step is to part the records and then prepared by the clusters of servers, for example, Java and R language on the servers. The target in this case is to assemble the data by a split depending on the words. The MapReduce pattern then consolidations the mix/sort results for information to the reducer program, which thencalculates the number of times every word happens. This yield can then be input to an data warehouse where it might be consolidated with other information for analysis or accessed straight for wardly by different BI instruments .Figure 5. Hadoop ArchitectureV.RESULT AND DISCUSSIONBig data processing with spring framework results in distributed data store: spring framework enables resource and data aggregation on java. Java helps in improvement in execution efficiency by distributing application execution at different levels. Due to reducing costs of devices and networks data from real world is getting collected in data centres. A system that implements big data processing on spring framework is a combination of components like servers for judgment, accumulation and analysis to solve real life problems like traffic management and human resource management. Distributed parallel processing is required to perform statistical analysis of different vehicles at different or same place in one city or a comparison of different cities. In comparing with other distributed batch methods the performance increaseei ght times. Let us use this prototype to match any individual’s location and preference with product inventory of stores and malls and to generate the bills and deliver the product at the doorstep of customer in shortest possible time. The process shown in the figure can be explained in steps:Step 1: Individual’s location and preference is retrieved (Query 1)Step 2: Stores and malls details within a certain distance is retrieved (Query 2) Step 3: Individual’s information and store’s product information is matched (Query 3)Step 4: A bill is generated if they match.The processing load in step 2 and 3 is directly proportional to number of people. Dynamic load balancing by increasing dedicated servers reduces CPU usage and ensures high speed processing. Hence ensuring optimization of improvement in performance, resource efficiency and delivery synchronization.Figure 6. Architecture of big data with Spring FrameworkIn this figure 6 query 1, query 2, query 3 is based on spring framework of java that means all the query based code is stored in the given XML File, individual information is stored in oracle database. Finally coupon issued in the base of big data based query of spring framework of java and J2ee under the supervision Hadoop Architecture of Big Data follow in figure 7 shown below.Figure 7. Spring Framework with big dataVI. CONCLUSION AND FUTURE SCOPEIn this research article, we described the ongoing research to design and implement a big data with spring Framework.This model administers big data to ceaselessly trade asset cuts among machines, granting assets to those occupants requiring or qualified for additional, while having the capacity to figure out where the asset diminishment will be all the more financially compelling, i.e., will contribute in lesser degree to execution debasement.In future we have to implement big data with struts, spring and hibernate integration to reduce cost on infrastructure in java & J2ee base applications.中文译文基于Java/J2EE的Spring框架实现和分析大数据技术摘要—在JAVA Spring框架下的大数据技术时代,作为大数据中重要通道的Web服务器或应用服务器应该进行更新，以满足执行和强制要求。

JAVA学习过程论文中英文资料对照外文翻译文献

JAVA学习过程论文中英文资料对照外文翻译文献Java Learning Path processEach person's study method is different, a person's method suits another person not necessarily, I only can discuss own study method. Because I study Java am study independently completely, has not asked others, therefore the study process basically is completely oneself tries to find out. I did not know whether this method is the quite good method, only could give everybody to provide refers.Studies Java first step installs good JDK, writes Hello World? Actually the JDK study is not so simple, has two questions about JDK is very easy to puzzle the Java programmer continuously the place: Is the CLASSPATH question, actually said from the principle, is how must make clear JRE ClassLoader increase Class; Another question is package and the import question, how seeks the kind of way question. These two questions tried to find out clear, eliminated has studied Java and uses JDK the biggest barrier. The recommendation looked Wang Sen "the Java Depth Experiences dangers", has carried on the thorough discussion to these two questionsSecond step is studies Java the grammar. The Java grammar is kind of C++, the basically mainstream programming language is not kind of C, is kind of C++, does not have what new thing, therefore the grammar study, probably was the quite a while time is enough. Only needs to pay attention is has the key words usage which several is not easy to make clear, public, protected, private, static, when uses, why has to use, how uses, this possible need some people to direct, I initially was own ponder over completely, has spent the very long time. But afterwards I saw above this book spoke these concepts to "Thinking in Java".Third step is studies Java the object-oriented programming language characteristic place. For instance inherits, structure, abstract class, the connection, the method are many condition, heavy load, cover, Java exception handling mechanism. Said regarding a not object-oriented language background person that, I thought this process needs to spend the very long very long time, because studies in front of Java does not have C++ the experience, only then the C experience, I was have probably spent for a month, all made clear only then thoroughly these concepts, book example above repeatedly estimating, the revision, the attempt, repeatedly looked at that several chapter of contents, looked, looked has not gotten down 5, comprehended only then thoroughly. But I thought if has the C++ experience, should 12 days time be enough. Then in this process, may have a look "Thinking in Java" this book, opposite is extremely thorough to the object explanation. What a pity is I studies, has not seen to this book, therefore own have spent the massive time, and estimates through own attempt learns.Fourth step starts a familiar Java kind of storehouse. The Java foundation class storehouse actually is JDK installs under the table of contentsjre\Lib\Rt.Jar this package. The study foundation class storehouse studies rt.Jar. Inside the foundation class storehouse kind are extremely extremely many. It is said some more than 3,000, I have not counted. But said the most core truly regarding us only then 4, respectively isng.*;Java.Io.*;Java.Util.*;Java.Sql.*;These four packages study, each package study all may write thick teaching material, but O'reilly also truly is does this. I thought if time quite tight, is impossible through to read four books to study. I thought the quite good study method is such:First must read through entire package the frame, understood entire package class, interface, the exception constitution, should better be can find the introduction entire package frame the article. These introduced specially package of books the first several chapters should be these overall frame content introductions. Is not must be familiar with each kind of usage to the package of overall frame assurance, which attributes remembers it have, the method. Wants to record also cannot remember. But is must know which aspects the package does have a kind of constitution, these kind of uses are any, most core several classifications maybe complete any function. I in the time which trains to the human generally is a class speaks a package, therefore not impossible detailed introduction each kind of usage, but I repeatedly stress, how do I speak these packages to you am must tell you a kind of method am transfer, also does not request you to remember the kind of method transfer, but wants you tounderstand, which kinds Java has provided to us, each kind is uses in any situation, when I meet the question the time, I knew which kind, or which several kind of combinations can solve my problem, That'all! When we write the procedure specifically time, so long as you knew which kind should complete your work with to be enough. Codes, the concrete method transfer, writes the code, Documentation, all things all inside Documentation, will not request you certainly to remember, are actual you also not to be able to remember more than 3,000 kinds altogether the nearly 100,000 methods transfers. Therefore changes to each package overall frame assurance extremely importantly.Fifth step, through above study, if study the quite solid speech, built the Java foundation, is left over the work which had to do is sweeps clean inside Documentation besides above 4 packages other some comparisons to have the use the kind. Believed progressed to this step, Java studies independently the ability already to raise, might to study Documentation directly horizontal. Besides must make the GUI programming, inside JDK other can have the use the package is these:Java.Text.*;.*;Javax.Naming.*;These packages of inside real correct uses quite many kinds very are actually few, only then several, therefore does not need to spend the very much time.Sixth step, Java Web programmingThe Web programming core is the HTTP agreement, the HTTP agreement and Java irrelevant, if not familiar HTTP agreement, although also may learnServlet/JSP programming, but cannot achieve extrapolates, by knowing one method you will know all boundary. Therefore the HTTP agreement study is necessary. If has been familiar with HTTP agreement, also had the Java programming good foundation, studies Servlet/JSP is simply easy as pie, I study Servlet/JSP has used not to week-long time, then started with JSP to make the project. In Servlet/In the JSP study, heavy still was Servlet Documentation. Servlet the API most commonly used kind are very few, the flowered quite few time might grasp. These kinds all looked at, writes several examples to try. Servlet/The JSP programming essence is transferring these kinds to come repeatedly through the HTTP agreement converses between Web Server and Brower. Moreover to JSP, but also needs to be familiar with several commonly used JSP the mark, the concrete mode of writing cannot remember the speech, looks up temporarily and that's the end of.In addition Java the Web programming study must place Web Application with emphasis in the design pattern, how carries on the service logic the analysis, and carries on the reasonable design, according to the MVC design pattern request, completes the different logical level separately using Servlet and JSP, how grasps carries on the flow between Servlet and JSP the control and data sharing, as well as how Web should Application dispose and the deployment.Seventh step, J2EE programmingThe above study process if is quite smooth, carries on to this step, the difficulty enhances suddenly. Because the above knowledge content all only involves an aspect, but likes EJB, JMS, core the and so on JTA J2EE standard often is several kind of Java technology synthesis utilization crystallization, therefore grasps the difficulty quite to be big.First certainly must study good JNDI, JNDI is App the Server localization server resources (the EJB module, Datasouce, JMS) searches the method, if to JNDI not familiar, EJB, JMS these things cannot study nearly. JNDI actually is javax.Naming.* This package, utilizes is very simple. The difficulty lies in the server resources document the disposition. Regarding the server resources document disposition, needed to have a look the special documents to be standard, for instance web.Xml mode of writing, ejb-jar.Xml mode of writing and so on. In view of each kind of different App Server, but also has own service resources disposition document, also is needs to be familiar with.Then may study JTA, mainly is must understand JTA regarding business control method, as well as should use JTA in any situation. Here may simple cite an example, we knew the ordinary circumstances may carry on business regarding a database connection (conn.SetAutoCommit (false)....,mit ()), does is an atomic operation, but the supposition my service demand is needs to hold artificially to two different databases is an atomic operation, you can do to? At this time only could use JTA. The supposition operating process inserts a record first toward the A database, then deletes the B database another record, we wrote the code are cannot control entire hold artificially are an atomic operation. With the JTA speech, completes the control by App Server.In studies in front of EJB must study the object sequence and RMI, RMI is the EJB foundation. Then studies JMS and EJB, said regarding EJB, most is essential is must understand how EJB is realizes through RMI to the far-end object transfer, as well as must use in any situation to EJB.In studies EJB, after JMS these things, you possibly can realize must extremely anxiously study two domains the knowledge, is UML, another isDesign Pattern. The Java enterprise software design takes the frame extremely (Framework) the design, a good software frame is the software develops the successful essential condition. In this time, should start the study key point to place the design pattern and in the frame study, experiences through the study and the actual programming grasps EJB the design pattern and the J2EE core pattern.Inside J2EE standard, except EJB, JMS, JTA, Servlet/JSP, outside JDBC also has the very many very many enterprises technology, here 11 did not carry on introducedMoreover also has newest domain Web Services. Web Services also completely does not have any new thing, it likes is one kind of adhesive, may unify the different service provides a unified transfer connection, said as the user, I so long as obtain the service provider for mine WSDL (to service description), has sufficed, I did not know completely the server tenderer provides actually the service is the EJB module,The Net module, any CORBA module, other any realizations, I do not need to know. Web the Services greatest place lies in through the unified service provides the way and the transfer way, has realized the entire Internet service sharing, is an extremely excited area of technology. Web Services resembles at present not to have any very good books, but may through look up the material above the network the way to study.JA V A学习过程每个人的学习方法是不同的，一个人的方法不见得适合另一个人，我只能是谈自己的学习方法。

在线图书管理系统外文文献原文及译文

毕业设计说明书英文文献及中文翻译班姓名：学院：专指导教师：2014 年 6 月软件学院软件工程An Introduction to JavaThe first release of Java in 1996 generated an incredible amount of excitement, not just in the computer press, but in mainstream media such as The New York Times, The Washington Post, and Business Week. Java has the distinction of being the first and only programming language that had a ten-minute story on National Public Radio. A $100,000,000 venture capital fund was set up solely for products produced by use of a specific computer language. It is rather amusing to revisit those heady times, and we give you a brief history of Java in this chapter.In the first edition of this book, we had this to write about Java: “As a computer language, Java’s hype is overdone: Java is certainly a good program-ming language. There is no doubt that it is one of the better languages available to serious programmers. We think it could potentially have been a great programming language, but it is probably too late for that. Once a language is out in the field, the ugly reality of compatibility with existing code sets in.”Our editor got a lot of flack for this paragraph from someone very high up at Sun Micro- systems who shall remain unnamed. But, in hindsight, our prognosis seems accurate. Java has a lot of nice language features—we examine them in detail later in this chapter. It has its share of warts, and newer additions to the language are not as elegant as the original ones because of the ugly reality of compatibility.But, as we already said in the first edition, Java was never just a language. There are lots of programming languages out there, and few of them make much of a splash. Java is a whole platform, with a huge library, containing lots of reusable code, and an execution environment that provides services such as security, portability across operating sys-tems, and automatic garbage collection.As a programmer, you will want a language with a pleasant syntax and comprehensible semantics (i.e., not C++). Java fits the bill, as do dozens of other fine languages. Some languages give you portability, garbage collection, and the like, but they don’t have much of a library, forcing you to roll your own if you want fancy graphics or network- ing or database access. Well, Java has everything—a good language, a high-quality exe- cution environment, and a vast library. That combination is what makes Java an irresistible proposition to so many programmers.SimpleWe wanted to build a system that could be programmed easily without a lot of eso- teric training and which leveraged t oday’s standard practice. So even though wefound that C++ was unsuitable, we designed Java as closely to C++ as possible in order to make the system more comprehensible. Java omits many rarely used, poorly understood, confusing features of C++ that, in our experience, bring more grief than benefit.The syntax for Java is, indeed, a cleaned-up version of the syntax for C++. There is no need for header files, pointer arithmetic (or even a pointer syntax), structures, unions, operator overloading, virtual base classes, and so on. (See the C++ notes interspersed throughout the text for more on the differences between Java and C++.) The designers did not, however, attempt to fix all of the clumsy features of C++. For example, the syn- tax of the switch statement is unchanged in Java. If you know C++, you will find the tran- sition to the Java syntax easy. If you are used to a visual programming environment (such as Visual Basic), you will not find Java simple. There is much strange syntax (though it does not take long to get the hang of it). More important, you must do a lot more programming in Java. The beauty of Visual Basic is that its visual design environment almost automatically pro- vides a lot of the infrastructure for an application. The equivalent functionality must be programmed manually, usually with a fair bit of code, in Java. There are, however, third-party development environments that provide “drag-and-drop”-style program development.Another aspect of being simple is being small. One of the goals of Java is to enable the construction of software that can run stand-alone in small machines. The size of the basic interpreter and class support is about 40K bytes; adding the basic stan- dard libraries and thread support (essentially a self-contained microkernel) adds an additional 175K.This was a great achievement at the time. Of course, the library has since grown to huge proportions. There is now a separate Java Micro Edition with a smaller library, suitable for embedded devices.Object OrientedSimply stated, object-oriented design is a technique for programming that focuses on the data (= objects) and on the interfaces to that object. To make an analogy with carpentry, an “object-oriented” carpenter would be mostly concerned with the chair he was building, and secondari ly with the tools used to make it; a “non-object- oriented” carpenter would think primarily of his tools. The object-oriented facilities of Java are essentially those of C++.Object orientation has proven its worth in the last 30 years, and it is inconceivable that a modern programming language would not use it. Indeed, the object-oriented features of Java are comparable to those of C++. The major difference between Java and C++ lies in multiple inheritance, which Java has replaced with the simpler concept of interfaces, and in the Java metaclass model (which we discuss in Chapter 5). NOTE: If you have no experience with object-oriented programming languages, you will want to carefully read Chapters 4 through 6. These chapters explain what object-oriented programming is and why it is more useful for programming sophisticated projects than are traditional, procedure-oriented languages like C or Basic.Network-SavvyJava has an extensive library of routines for coping with TCP/IP protocols like HTTP and FTP. Java applications can open and access objects across the Net via URLs with the same ease as when accessing a local file system.We have found the networking capabilities of Java to be both strong and easy to use. Anyone who has tried to do Internet programming using another language will revel in how simple Java makes onerous tasks like opening a socket connection. (We cover net- working in V olume II of this book.) The remote method invocation mechanism enables communication between distributed objects (also covered in V olume II).RobustJava is intended for writing programs that must be reliable in a variety of ways.Java puts a lot of emphasis on early checking for possible problems, later dynamic (runtime) checking, and eliminating situations that are error-prone. The single biggest difference between Java and C/C++ is that Java has a pointer model that eliminates the possibility of overwriting memory and corrupting data.This feature is also very useful. The Java compiler detects many problems that, in other languages, would show up only at runtime. As for the second point, anyone who has spent hours chasing memory corruption caused by a pointer bug will be very happy with this feature of Java.If you are coming from a language like Visual Basic that doesn’t explicitly use pointers, you are probably wondering why this is so important. C programmers are not so lucky. They need pointers to access strings, arrays, objects, and even files. In Visual Basic, you do not use pointers for any of these entities, nor do you need to worry about memory allocation for them. On the other hand, many data structures are difficult to implementin a pointerless language. Java gives you the best of both worlds. You do not need point- ers for everyday constructs like strings and arrays. You have the power of pointers if you need it, for example, for linked lists. And you always have complete safety, because you can never access a bad pointer, make memory allocation errors, or have to protect against memory leaking away.Architecture NeutralThe compiler generates an architecture-neutral object file format—the compiled code is executable on many processors, given the presence of the Java runtime sys- tem. The Java compiler does this by generating bytecode instructions which have nothing to do with a particular computer architecture. Rather, they are designed to be both easy to interpret on any machine and easily translated into native machine code on the fly.This is not a new idea. More than 30 years ago, both Niklaus Wirth’s original implemen- tation of Pascal and the UCSD Pascal system used the same technique.Of course, interpreting bytecodes is necessarily slower than running machine instruc- tions at full speed, so it isn’t clear that this is even a good idea. However, virtual machines have the option of translating the most frequently executed bytecode sequences into machine code, a process called just-in-time compilation. This strategy has proven so effective that even Microsoft’s .NET platform relies on a virt ual machine.The virtual machine has other advantages. It increases security because the virtual machine can check the behavior of instruction sequences. Some programs even produce bytecodes on the fly, dynamically enhancing the capabilities of a running program.PortableUnlike C and C++, there are no “implementation-dependent” aspects of the specifi- cation. The sizes of the primitive data types are specified, as is the behavior of arith- metic on them.For example, an int in Java is always a 32-bit integer. In C/C++, int can mean a 16-bit integer, a 32-bit integer, or any other size that the compiler vendor likes. The only restriction is that the int type must have at least as many bytes as a short int and cannot have more bytes than a long int. Having a fixed size for number types eliminates a major porting headache. Binary data is stored and transmitted in a fixed format, eliminating confusion about byte ordering. Strings are saved in a standard Unicode format. The libraries that are a part of the system define portable interfaces. For example,there is an abstract Window class and implementations of it for UNIX, Windows, and the Macintosh.As anyone who has ever tried knows, it is an effort of heroic proportions to write a pro- gram that looks good on Windows, the Macintosh, and ten flavors of UNIX. Java 1.0 made the heroic effort, delivering a simple toolkit that mapped common user interface elements to a number of platforms. Unfortunately, the result was a library that, with a lot of work, could give barely acceptable results on different systems. (And there were often different bugs on the different platform graphics implementations.) But it was a start. There are many applications in which portability is more important than user interface slickness, and these applications did benefit from early versions of Java. By now, the user interface toolkit has been completely rewritten so that it no longer relies on the host user interface. The result is far more consistent and, we think, more attrac- tive than in earlier versions of Java.InterpretedThe Java interpreter can execute Java bytecodes directly on any machine to which the interpreter has been ported. Since linking is a more incremental and lightweight process, the development process can be much more rapid and exploratory.Incremental linking has advantages, but its benefit for the development process is clearly overstated. Early Java development tools were, in fact, quite slow. Today, the bytecodes are translated into machine code by the just-in-time compiler.MultithreadedThe benefits of multithreading are better interactive responsiveness and real-time behavior.If you have ever tried to do multithreading in another language, you will be pleasantly surprised at how easy it is in Java. Threads in Java also can take advantage of multi- processor systems if the base operating system does so. On the downside, thread imple- mentations on the major platforms differ widely, and Java makes no effort to be platform independent in this regard. Only the code for calling multithreading remains the same across machines; Java offloads the implementation of multithreading to the underlying operating system or a thread library. Nonetheless, the ease of multithread- ing is one of the main reasons why Java is such an appealing language for server-side development.Java程序设计概述1996年Java第一次发布就引起了人们的极大兴趣。

计算机科学与技术Java垃圾收集器中英文对照外文翻译文献

中英文资料中英文资料外文翻译文献原文：How a garbage collector works of Java LanguageIf you come from a programming language where allocating objects on the heap is expensive, you may naturally assume that Java’s scheme of allocating everything (except primitives) on the heap is also expensive. However, it turns out that the garbage collector can have a significant impact on increasing the speed of object creation. This might sound a bit odd at first—that storage release affects storage allocation—but it’s the way some JVMs work, and it means that allocating storage for heap objects in Java can be nearly as fast as creating storage on the stack in other languages.For example, you can think of the C++ heap as a yard where each stakes out its own piece of turf object. This real estate can become abandoned sometime later and must be reused. In some JVMs, the Java heap is quite different; it’s more like a conveyor belt that moves forwardevery time you allocate a new object. This means that object storage allocation is remarkab ly rapid. The “heap pointer” is simply moved forward into virgin territory, so it’s effectively the same as C++’s stack allocation. (Of course, there’s a little extra overhead for bookkeeping, but it’s nothing like searching for storage.)You might observ e that the heap isn’t in fact a conveyor belt, and if you treat it that way, you’ll start paging memory—moving it on and off disk, so that you can appear to have more memory than you actually do. Paging significantly impacts performance. Eventually, after you create enough objects, you’ll run out of memory. The trick is that the garbage collector steps in, and while it collects the garbage it compacts all the objects in the heap so that you’ve effectively moved the “heap pointer” closer to the beginning of the conveyor belt and farther away from a page fault. The garbage collector rearranges things and makes it possible for the high-speed, infinite-free-heap model to be used while allocating storage.To understand garbage collection in Java, it’s helpful le arn how garbage-collection schemes work in other systems. A simple but slow garbage-collection technique is called reference counting. This means that each object contains a reference counter, and every time a reference is attached to that object, the reference count is increased. Every time a reference goes out of scope or is set to null, the reference count isdecreased. Thus, managing reference counts is a small but constant overhead that happens throughout the lifetime of your program. The garbage collector moves through the entire list of objects, and when it finds one with a reference count of zero it releases that storage (however, reference counting schemes often release an object as soon as the count goes to zero). The one drawback is that if objects circularly refer to each other they can have nonzero reference counts while still being garbage. Locating such self-referential groups requires significant extra work for the garbage collector. Reference counting is commonly used to explain one kind of g arbage collection, but it doesn’t seem to be used in any JVM implementations.In faster schemes, garbage collection is not based on reference counting. Instead, it is based on the idea that any non-dead object must ultimately be traceable back to a reference that lives either on the stack or in static storage. The chain might go through several layers of objects. Thus, if you start in the stack and in the static storage area and walk through all the references, you’ll find all the live objects. For each reference that you find, you must trace into the object that it points to and then follow all the references in that object, tracing into the objects they point to, etc., until you’ve moved through the entire Web that originated with the reference on the stack or in static storage. Each object that you move through must still be alive. Note that there is no problem withdetached self-referential groups—these are simply not found, and are therefore automatically garbage.In the approach described here, the JVM uses an adaptive garbage-collection scheme, and what it does with the live objects that it locates depends on the variant currently being used. One of these variants is stop-and-copy. This means that—for reasons that will become apparent—the program is first stopped (this is not a background collection scheme). Then, each live object is copied from one heap to another, leaving behind all the garbage. In addition, as the objects are copied into the new heap, they are packed end-to-end, thus compacting the new heap (and allowing new storage to simply be reeled off the end as previously described).Of course, when an object is moved from one place to another, all references that point at the object must be changed. The reference that goes from the heap or the static storage area to the object can be changed right away, but there can be other references pointing to this object Initialization & Cleanup that will be encountered later during the “walk.” These are fixed up as they are found (you could imagine a table that maps old addresses to new ones).There are two issues that make these so-called “copy collectors” inefficient. The first is the idea that you have two heaps and you slosh all the memory back and forth between these two separate heaps,maintaining twice as much memory as you actually need. Some JVMs deal with this by allocating the heap in chunks as needed and simply copying from one chunk to another.The second issue is the copying process itself. Once your program becomes stable, it might be generating little or no garbage. Despite that, a copy collector will still copy all the memory from one place to another, which is wasteful. To prevent this, some JVMs detect that no new garbage is being generated and switch to a different scheme (this is the “adaptive” part). This other scheme is called mark-and-sweep, and it’s what earlier versions of Sun’s JVM used all the time. For general use, mark-and-sweep is fairly slow, but when you know you’re generating little or no garbage, it’s fast. Mark-and-sweep follows the same logic of starting from the stack and static storage, and tracing through all the references to find live objects.However, each time it finds a live object, that object is marked by setting a flag in it, but the object isn’t collected yet.Only when the marking process is finished does the sweep occur. During the sweep, the dead objects are released. However, no copying happens, so if the collector chooses to compact a fragmented heap, it does so by shuffling objects around. “Stop-and-copy”refers to the idea that this type of garbage collection is not done in the background; Instead, the program is stopped while the garbage collection occurs. In the Sun literature you’llfind many references to garbage collection as a low-priority background process, but it turns out that the garbage collection was not implemented that way in earlier versions of the Sun JVM. Instead, the Sun garbage collector stopped the program when memory got low. Mark-and-sweep also requires that the program be stopped.As previously mentioned, in the JVM described here memory is allocated in big blocks. If you allocate a large object, it gets its own block. Strict stop-and-copy requires copying every live object from the source heap to a new heap before you can free the old one, which translates to lots of memory. With blocks, the garbage collection can typically copy objects to dead blocks as it collects. Each block has a generation count to keep track of whether it’s alive. In the normal case, only the blocks created since the last garbage collection are compacted; all other blocks get their generation count bumped if they have been referenced from somewhere. This handles the normal case of lots of short-lived temporary objects. Periodically, a full sweep is made—large objects are still not copied (they just get their generation count bumped), and blocks containing small objects are copied and compacted.The JVM monitors the efficiency of garbage collection and if it becomes a waste of time because all objects are long-lived, then it switches to mark-and sweep. Similarly, the JVM keeps track of how successful mark-and-sweep is, and if the heap starts to becomefragmented, it switches back to stop-and-copy. This is where the “adaptive” part comes in, so you end up with a mouthful: “Adaptive generational stop-and-copy mark-and sweep.”There are a number of additional speedups possible in a JVM. An especially important one involves the operation of the loader and what is called a just-in-time (JIT) compiler. A JIT compiler partially or fully converts a program into native machine code so that it doesn’t need to be interpreted by the JVM and thus runs much faster. When a class must be loaded (typically, the first time you want to create an object of that class), the .class file is located, and the byte codes for that class are brought into memory. At this point, one approach is to simply JIT compile all the code, but this has two drawbacks: It takes a little more time, which, compounded throughout the life of the program, can add up; and it increases the size of the executable (byte codes are significantly more compact than expanded JIT code), and this might cause paging, which definitely slows down a program. An alternative approach is lazy evaluation, which means that the code is not JIT compiled until necessary. Thus, code that never gets executed might never be JIT compiled. The Java Hotspot technologies in recent JDKs take a similar approach by increasingly optimizing a piece of code each time it is executed, so the more the code is executed, the faster it gets.译文：Java垃圾收集器的工作方式如果你学下过一种因为在堆里分配对象所以开销过大的编程语言，很自然你可能会假定Java 在堆里为每一样东西（除了primitives）分配内存资源的机制开销也会很大。

JAVA外文文献+翻译说课讲解

Java and the InternetIf Java is, in fact, yet another computer programming language, you may question why it is so important and why it is being promoted as a revolutionary step in computer programming. The answer isn’t immediately obvious if you’re coming from a traditional programming perspective. Although Java is very useful for solving traditional stand-alone programming problems, it is also important because it will solve programming problems on the World Wide Web.1.Client-side programmingThe Web’s in itial server-browser design provided for interactive content, but the interactivity was completely provided by the server. The server produced static pages for the client browser, which would simply interpret and display them. Basic HTML contains simple mechanisms for data gathering: text-entry boxes, check boxes, radio boxes, lists and drop-down lists, as well as a button that can only be programmed to reset the data on the form or “submit” the data on the form back to the server. This submission passes through the Common Gateway Interface (CGI) provided on all Web servers. The text within the submission tells CGI what to do with it. The most common action is to run a program located on the server in a directory that’s typically called “cgi-bin.” (If you watch the address window at the top of your browser when you push a button on a Web page, you can sometimes see “cgi-bin” within all the gobbledygook there.) These programs can be written in most languages. Perl is a common choice because it is designed for text manipulation and is interpreted, so it can be installed on any server regardless of processor or operating system. Many powerful Web sites today are built strictly on CGI, and you can in fact do nearly anything with it. However, Web sites built on CGI programs can rapidly become overly complicated to maintain, and there is also the problem of response time. The response of a CGI program depends on how much data mustbe sent, as well as the load on both the server and the Internet. (On top of this, starting a CGI program tends to be slow.) The initial designers of the Web did not foresee how rapidly this bandwidth would be exhausted for the kinds of applications people developed. For example, any sort of dynamic graphing is nearly impossible to perform with consistency because a GIF file must be created and moved from the server to the client for each version of the graph. And you’ve no doubt had direct experience with something as simple as validating the data on an input form. You press the submit button on a page; the data is shipped back to the server; the server starts a CGI program that discovers an error, formats an HTML page informing you of the error, and then sends the page back to you; you must then back up a page and try again. Not only is this slow, it’s inelegant.The solution is client-side programming. Most machines that run Web browsers are powerful engines capable of doing vast work, and with the original static HTML approach they are sitting there, just idly waiting for the server to dish up the next page. Client-side programming means that the Web browser is harnessed to do whatever work it can, and the result for the user is a much speedier and more interactive experience at your Web site.The problem with discussions of client-side prog ramming is that they aren’t very different from discussions of programming in general. The parameters are almost the same, but the platform is different: a Web browser is like a limited operating system. In the end, you must still program, and this accounts for the dizzying array of problems and solutions produced by client-side programming. The rest of this section provides an overview of the issues and approaches in client-side programming.2.Plug-insOne of the most significant steps forward in client-side programming is the development of the plug-in. This is a way for a programmer to add new functionality to the browser by downloading a piece of code that plugs itself into the appropriate spot in the browser. It tells the browser “from now on you canpe rform this new activity.” (You need to download the plug-in only once.) Some fast and powerful behavior is added to browsers via plug-ins, but writing a plug-in is not a trivial task, and isn’t something you’d want to do as part of the process of building a particular site. The value of the plug-in for client-side programming is that it allows an expert programmer to develop a new language and add that language to a browser without the permission of the browser manufacturer. Thus, plug-ins provide a “back door” that allows the creation of new client-side programming languages (although not all languages are implemented as plug-ins).3.Scripting languagesPlug-ins resulted in an explosion of scripting languages. With a scripting language you embed the source code for your client-side program directly into the HTML page, and the plug-in that interprets that language is automatically activated while the HTML page is being displayed. Scripting languages tend to be reasonably easy to understand and, because they are simply text that is part of an HTML page, they load very quickly as part of the single server hit required to procure that page. The trade-off is that your code is exposed for everyone to see (and steal). Generally, however, you aren’t doing amazingly s ophisticated things with scripting languages so this is not too much of a hardship.This points out that the scripting languages used inside Web browsers are really intended to solve specific types of problems, primarily the creation of richer and more interactive graphical user interfaces (GUIs). However, a scripting language might solve 80 percent of the problems encountered in client-side programming. Your problems might very well fit completely within that 80 percent, and since scripting languages can allow easier and faster development, you should probably consider a scripting language before looking at a more involved solution such as Java or ActiveX programming.The most commonly discussed browser scripting languages are JavaScript (which has nothing to do with Java; it’s named that way just to grab some of Java’s marketing momentum), VBScript (which looks like Visual Basic), andTcl/Tk, which comes from the popular cross-platform GUI-building language. There are others out there, and no doubt more in development.JavaScript is probably the most commonly supported. It comes built into both Netscape Navigator and the Microsoft Internet Explorer (IE). In addition, there are probably more JavaScript books available than there are for the other browser languages, and some tools automatically create pages using JavaScript. However, if you’re already fluent in Visual Basic or Tcl/Tk, you’ll be more productive using those scripting languages rather than learning a new one. (You’ll have your hands full dealing w ith the Web issues already.)4.JavaIf a scripting language can solve 80 percent of the client-side programming problems, what about the other 20 percent—the “really hard stuff?” The most popular solution today is Java. Not only is it a powerful programming language built to be secure, cross-platform, and international, but Java is being continually extended to provide language features and libraries that elegantly handle problems that are difficult in traditional programming languages, such as multithreading, database access, network programming, and distributed computing. Java allows client-side programming via the applet.An applet is a mini-program that will run only under a Web browser. The applet is downloaded automatically as part of a Web page (just as, for example, a graphic is automatically downloaded). When the applet is activated it executes a program. This is part of its beauty—it provides you with a way to automatically distribute the client software from the server at the time the user needs the client software, and no sooner. The user gets the latest version of the client software without fail and without difficult reinstallation. Because of the way Java is designed, the programmer needs to create only a single program, and that program automatically works with all computers that have browsers with built-in Java interpreters. (This safely includes the vast majority of machines.) Since Java is a full-fledged programming language, you can do as much work as possible on the client before and after making requests of theserver. For example, you won’t need to send a request form across the Internet to discover that you’ve gotten a date or some other parameter wrong, and your client computer can quickly do the work of plotting data instead of waiting for the server to make a plot and ship a graphic image back to you. Not only do you get the immediate win of speed and responsiveness, but the general network traffic and load on servers can be reduced, preventing the entire Internet from slowing down.On e advantage a Java applet has over a scripted program is that it’s in compiled form, so the source code isn’t available to the client. On the other hand, a Java applet can be decompiled without too much trouble, but hiding your code is often not an important issue. Two other factors can be important. As you will see later in this book, a compiled Java applet can comprise many modules and take multiple server “hits” (accesses) to download. (In Java 1.1 and higher this is minimized by Java archives, called JAR files, that allow all the required modules to be packaged together and compressed for a single download.) A scripted program will just be integrated into the Web page as part of its text (and will generally be smaller and reduce server hits). This could be important to the responsiveness of your Web site. Another factor is the all-important learning curve. Regardless of what you’ve heard, Java is not a trivial language to learn. If you’re a Visual Basic programmer, moving to VBScript will be your fastest solution, and since it will probably solve most typical client/server problems you might be hard pressed to justify learning Java. If you’re experienced with a scripting language you will certainly benefit from looking at JavaScript or VBScript before committing to Java, since they might fit your needs handily and you’ll be more productive sooner.to run its applets withi5.ActiveXTo some degree, the competitor to Java is Microsoft’s ActiveX, although it takes a completely different approach. ActiveX was originally a Windows-only solution, although it is now being developed via an independent consortium to become cross-platform. Effectively, ActiveX says “if your program connects toits environment just so, it can be dropped into a Web page and run under a b rowser that supports ActiveX.” (IE directly supports ActiveX and Netscape does so using a plug-in.) Thus, ActiveX does not constrain you to a particular language. If, for example, you’re already an experienced Windows programmer using a language such as C++, Visual Basic, or Borland’s Delphi, you can create ActiveX components with almost no changes to your programming knowledge. ActiveX also provides a path for the use of legacy code in your Web pages.6.SecurityAutomatically downloading and running programs across the Internet can sound like a virus-builder’s dream. ActiveX especially brings up the thorny issue of security in client-side programming. If you click on a Web site, you might automatically download any number of things along with the HTML page: GIF files, script code, compiled Java code, and ActiveX components. Some of these are benign; GIF files can’t do any harm, and scripting languages are generally limited in what they can do. Java was also designed to run its applets within a “sandbox” of s afety, which prevents it from writing to disk or accessing memory outside the sandbox.ActiveX is at the opposite end of the spectrum. Programming with ActiveX is like programming Windows—you can do anything you want. So if you click on a page that downloads an ActiveX component, that component might cause damage to the files on your disk. Of course, programs that you load onto your computer that are not restricted to running inside a Web browser can do the same thing. Viruses downloaded from Bulletin-Board Systems (BBSs) have long been a problem, but the speed of the Internet amplifies the difficulty.The solution seems to be “digital signatures,” whereby code is verified to show who the author is. This is based on the idea that a virus works because its creator can be anonymous, so if you remove the anonymity individuals will be forced to be responsible for their actions. This seems like a good plan because it allows programs to be much more functional, and I suspect it will eliminate malicious mischief. If, however, a program has an unintentional destructive bugit will still cause problems.The Java approach is to prevent these problems from occurring, via the sandbox. The Java interpreter that lives on your local Web browser examines the applet for any untoward instructions as the applet is being loaded. In particular, the applet cannot write files to disk or erase files (one of the mainstays of viruses). Applets are generally considered to be safe, and since this is essential for reliable client/server systems, any bugs in the Java language that allow viruses are rapidly repaired. (It’s worth noting that the browser software actually enforces these security restrictions, and some browsers allow you to select different security levels to provide varying degrees of access to your system.) You might be skeptical of this rather draconian restriction against writing files to your local disk. For example, you may want to build a local database or save data for later use offline. The initial vision seemed to be that eventually everyone would get online to do anything important, but that was soon seen to be impractical (although low-cost “Internet appliances” might someday satisfy the needs of a significant segment of users). The solution is the “signed applet” that uses public-key encryption to verify that an applet does indeed come from where it claims it does. A signed applet can still trash your disk, but the theory is that since you can now hold the applet creator accountable they won’t do vicious things. Java provides a framework for digital signatures so that you will eventually be able to allow an applet to step outside the sandbox if necessary. Digital signatures have missed an important issue, which is the speed that people move around on the Internet. If you download a buggy program and it does something untoward, how long will it be before you discover the damage? It could be days or even weeks. By then, how will you track down the program that’s done it? And what good will it do you at that point?7.Internet vs. intranetThe Web is the most general solution to the client/server problem, so it makes sense that you can use the same technology to solve a subset of the problem, in particular the classic client/server problem within a company. With traditionalclient/server approaches you have the problem of multiple types of client computers, as well as the difficulty of installing new client software, both of which are handily solved with Web browsers and client-side programming. When Web technology is used for an information network that is restricted to a particular company, it is referred to as an intranet. Intranets provide much greater security than the Internet, since you can physically control access to the servers within your company. In terms of training, it seems that once people understand the general concept of a browser it’s much easier for them to deal with differences in the way pages and applets look, so the learning curve for new kinds of systems seems to be reduced.The security problem brings us to one of the divisions that seems to be automatically forming in the world of client-side programming. If your program is running on the Internet, you don’t know what platform it will be working under, and you want to be extra careful that you don’t di sseminate buggy code. You need something cross-platform and secure, like a scripting language or Java.If you’re running on an intranet, you might have a different set of constraints. It’s not uncommon that your machines could all be Intel/Windows platfor ms. On an intranet, you’re responsible for the quality of your own code and can repair bugs when they’re discovered. In addition, you might already have a body of legacy code that you’ve been using in a more traditional client/server approach, whereby you must physically install client programs every time you do an upgrade. The time wasted in installing upgrades is the most compelling reason to move to browsers, because upgrades are invisible and automatic. If you are involved in such an intranet, the most sensible approach to take is the shortest path that allows you to use your existing code base, rather than trying to recode your programs in a new language.When faced with this bewildering array of solutions to the client-side programming problem, the best plan of attack is a cost-benefit analysis. Consider the constraints of your problem and what would be the shortest path to your solution. Since client-side programming is still programming, it’s always a good idea to take the fastest development approach for your particular situation.This is an aggressive stance to prepare for inevitable encounters with the problems of program development.8.Server-side programmingThis whole discussion has ignored the issue of server-side programming. What happens when you make a request of a server? Most of the time the request is simply “send me this file.” Your browser then interprets the file in some appropriate fashion: as an HTML page, a graphic image, a Java applet, a script program, etc. A more complicated request to a server generally involves a database transaction. A common scenario involves a request for a complex database search, which the server then formats into an HTML page and sends to you as the result. (Of course, if the client has more intelligence via Java or a scripting language, the raw data can be sent and formatted at the client end, which will be faster and less load on the server.) Or you might want to register your name in a database when you join a group or place an order, which will involve changes to that database. These database requests must be processed via some code on the server side, which is generally referred to as server-side programming. Traditionally, server-side programming has been performed using Perl and CGI scripts, but more sophisticated systems have been appearing. These include Java-based Web servers that allow you to perform all your server-side programming in Java by writing what are called servlets. Servlets and their offspring, JSPs, are two of the most compelling reasons that companies who develop Web sites are moving to Java, especially because they eliminate the problems of dealing with differently abled browsers.9. separate arena: applicationsMuch of the brouhaha over Java has been over applets. Java is actually a general-purpose programming language that can solve any type of problem—at least in theory. And as pointed out previously, there might be more effective ways to solve most client/server problems. When you move out of the appletarena (and simultaneously release the restrictions, such as the one against writing to disk) you enter the world of general-purpose applications that run standalone, without a Web browser, just like any ordinary program does. Here, Java’s strength is not only in its portability, but a lso its programmability. As you’ll see throughout this book, Java has many features that allow you to create robust programs in a shorter period than with previous programming languages. Be aware that this is a mixed blessing. You pay for the improvements through slower execution speed (although there is significant work going on in this area—JDK 1.3, in particular, introduces the so-called “hotspot” performance improvements). Like any language, Java has built-in limitations that might make it inappropriate to solve certain types of programming problems. Java is a rapidly evolving language, however, and as each new release comes out it becomes more and more attractive for solving larger sets of problems.Java和因特网既然Java不过另一种类型的程序设计语言，大家可能会奇怪它为什么值得如此重视，为什么还有这么多的人认为它是计算机程序设计的一个里程碑呢？如果您来自一个传统的程序设计背景，那么答案在刚开始的时候并不是很明显。

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1. Client-side programming The Web’s initial server-browser design provided for interactive content, but the interactivity was completely provided by the server. The server produced static pages for the client browser, which would simply interpret and display them. Basic HTML contains simple mechanisms for data gathering: text-entry boxes, check boxes, radio boxes, lists and drop-down lists, as well as a button that can only be programmed to reset the data on the form or “submit” the data on the form back to the server. This submission passes through the Common Gateway Interface (CGI) provided on all Web servers. The text within the submission tells CGI what to do with it. The most common action is to run a program located on the server in a directory that’s typically called “cgi-bin.” (If you watch the address window at the top of your browser when you push a button on a Web page, you can sometimes see “cgi-bin” within all the gobbledygook there.) These programs can be written in most languages. Perl is a common choice because it is designed for text manipulation and is interpreted, so it can be installed on any server regardless of processor or operating system. Many powerful Web sites today are built strictly on CGI, and you can in fact do nearly anything with it. However, Web sites built on CGI programs can rapidly become overly complicated to maintain, and there is also the problem of response time. The response of a CGI program depends on how much data must be sent, as well as the load on both the server and the Internet. (On top of this, starting a CGI program tends to be slow.) The initial designers of the Web did not foresee how rapidly this bandwidth would be exhausted for the kinds of applications people developed. For example, any sort of dynamic graphing is nearly impossible to perform with consistency because a GIF file must be created and moved from the server to the client for each version of the graph. And you’ve no doubt had direct experience with something as simple as validating the data on an input form. You press the submit button on a page; the data is shipped back to the server; the server starts a CGI program that discovers an error, formats an HTML page informing you of the error, and then sends the page back to you; you must then back up a page and try again. Not only is this slow, it’s inelegant. The solution is client-side programming. Most machines that run Web browsers are powerful engines capable of doing vast work, and with the original static HTML approach they are sitting there, just idly waiting for the server to dish up the next page. Client-side programming means that the Web browser is harnessed to do whatever work it can, and the result for the user is a much speedier and more interactive experience at your Web site. The problem with discussions of client-side programming is that they aren’t very different from discussions of programming in general. The parameters are almost the same, but the platform is different: a Web browser is like a limited operating system. In the end, you must still program, and this accounts for the dizzying array of problems and solutions produced by client-side programming. The rest of this section provides an overview of the issues and approaches in client-side programming.

2.Plug-ins One of the most significant steps forward in client-side programming is the development of the plug-in. This is a way for a programmer to add new functionality to the browser by downloading a piece of code that plugs itself into the appropriate spot in the browser. It tells the browser “from now on you can perform this new activity.” (You need to download the plug-in only once.) Some fast and powerful behavior is added to browsers via plug-ins, but writing a plug-in is not a trivial task, and isn’t something you’d want to do as part of the process of building a particular site. The value of the plug-in for client-side programming is that it allows an expert programmer to develop a new language and add that language to a browser without the permission of the browser manufacturer. Thus, plug-ins provide a “back door” that allows the creation of new client-side programming languages (although not all languages are implemented as plug-ins).