外文翻译原文及译文学 院计算机学院专 业计算机科学与技术班 级学 号姓 名指导教师负责教师Java(programming language)Javais ageneral-purpose,concurrent,class-based,object-orientedcomputer program- -ming languagethat is specifically designed to have as few implementation dependencies as possible. It is intended to let application developers write once, run anywhere (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. Java applications are typicallycompiledtobyte code(class file) that can run on anyJava virtual machine(JVM) regardless ofcomputer architecture. Java is, as of 2012, one of the most popular programming languages in use, particularly for client-server web applications, with a reported 10 million users.Java was originally developed byJames GoslingatSun Microsystems(which has sincemerged into Oracle Corporation) and released in 1995 as a core component of Sun MicrosystemsJava platform. The language derives much of itssyntaxfromCandC+, but it has fewer low-levelfacilities than either of them.The original andreference implementationJavacompilers, virtual machines, andclass librarieswere developed by Sun from 1991 and first released in 1995. As of May 2007, in compliance with the specifications of theJava Community Process, Sun relicensed most of its Java technologies under theGNU General Public License. Others have also developed alternative implementations of these Sun technologies, such as theGNU Compiler for JavaandGNU Classpath.Javais a set of severalcomputer softwareproducts and specifications fromSun Microsystems(which has since merged withOracle Corporation), that together provide a system for developingapplication softwareand deploying it in across-platformcomputing environment. Java is used in a wide variety ofcomputing platformsfromembedded devicesand mobile phoneson the low end, toenterprise serversandsupercomputerson the high end. While less common,Java appletsare sometimes used to provide improved and secure functions while browsing theWorld Wide Webondesktop computers.Writing in theJava programming languageis the primary way to produce code that will be deployed asJava bytecode. There are, however, byte codecompilersavailable for other languages such asAda,JavaScript,Python, andRuby. Several new languages have been designed to run natively on theJava Virtual Machine(JVM), such asScala,ClojureandGroovy.Java syntaxborrows heavily fromCandC+, but object-oriented features are modeled afterSmalltalkandObjective-C. Java eliminates certain low-level constructs such aspointersand has a very simple memory model where every object is allocated on the heapand all variables of object types arereferences. Memory management is handled through integrated automaticgarbage collectionperformed by the JVM.An edition of theJava platformis the name for a bundle of related programs from Sun that allow for developing and running programs written in theJavaprogramming language. The platform is not specific to any one processor oroperating system, but rather an execution engine (called avirtual machine) and a compiler with a set of libraries that are implemented for various hardware and operating systems so that Java programs can run identically on all of them. The Java platform consists of several programs, each of which provides a portion of its overall capabilities. For example, the Java compiler, which converts Java source code into Java byte code (an intermediate language for the JVM), is provided as part of theJava Development Kit(JDK). TheJava Runtime Environment(JRE), complementing the JVM with ajust-in-time (JIT) compiler, converts intermediate byte code into native machine code on the fly. An extensive set of libraries are also part of the Java platform.The essential components in the platform are the Java language compiler, the libraries, and the runtime environment in which Java intermediate byte code executes according to the rules laid out in the virtual machine specification.In most modernoperating systems(OSs), a large body of reusable code is provided to simplify the programmers job. This code is typically provided as a set of dynamically loadable librariesthat applications can call at runtime. Because the Java platform is not dependent on any specific operating system, applications cannot rely on any of the pre-existing OS libraries. Instead, the Java platform provides a comprehensive set of its own standard class libraries containing much of the same reusable functions commonly found in modern operating systems. Most of the system library is also written in Java. For instance,Swinglibrary paints the user interface and handles the events itself, eliminating many subtle differences between how different platforms handle even similar components.The Java class libraries serve three purposes withi