Java (software platform) - Wikipedia, the free encyclopedia. Java (software platform)The Java technology logo. Original author(s)James Gosling, Sun Microsystems. Developer(s)Oracle Corporation. Initial release. 23 January 1.
Java is used in a wide variety of computing platforms from embedded devices and mobile phones to enterprise servers and supercomputers. While they are less common than standalone Java applications, Java applets run in secure, sandboxed environments to provide many features of native applications and can be embedded in HTML pages. Writing in the Java programming language is the primary way to produce code that will be deployed as byte code in a Java Virtual Machine (JVM); byte code compilers are also available for other languages, including Ada, Java. Script, Python, and Ruby. In addition, several languages have been designed to run natively on the JVM, including Scala, Clojure and Apache Groovy. Java syntax borrows heavily from C and C++, but object- oriented features are modeled after Smalltalk and Objective- C. Memory management is handled through integrated automatic garbage collection performed by the JVM.
On November 1. 3, 2. Sun Microsystems made the bulk of its implementation of Java available under the GNU General Public License (GPL). Oracle states that using older versions presents serious risks due to unresolved security issues.
A Java platform will include an execution engine (called a virtual machine), a compiler and a set of libraries; there may also be additional servers and alternative libraries that depend on the requirements. Java is not specific to any processor or operating system as Java platforms have been implemented for a wide variety of hardware and operating systems with a view to enable Java programs to run identically on all of them. Different platforms target different classes of device and application domains: Java Card: A technology that allows small Java- based applications (applets) to be run securely on smart cards and similar small- memory devices.
Java ME (Micro Edition): Specifies several different sets of libraries (known as profiles) for devices with limited storage, display, and power capacities. It is often used to develop applications for mobile devices, PDAs, TV set- top boxes, and printers.
The Java programming language lies at the core of many large-scale business applications – especially business-to-business commercial systems that. Java Programming Tutorial - 2 - Running a Java Program. How to Run Java Program in Command Prompt in Windows 7.
Java SE (Standard Edition): For general- purpose use on desktop PCs, servers and similar devices. Java EE (Enterprise Edition): Java SE plus various APIs which are useful for multi- tierclient. For example, the Java compiler, which converts Java source code into Java bytecode (an intermediate language for the JVM), is provided as part of the Java Development Kit (JDK). The Java Runtime Environment (JRE), complementing the JVM with a just- in- time (JIT) compiler, converts intermediate bytecode into native machine code on the fly. The Java platform also includes an extensive set of libraries. The essential components in the platform are the Java language compiler, the libraries, and the runtime environment in which Java intermediate bytecode executes according to the rules laid out in the virtual machine specification. Java Virtual Machine.
Elements of Programming. Our goal in this chapter is to convince you that writing a computer program is easier than writing a piece of text such as a. Java (programming language) Not to be confused with. Bu kod bir Java derleyicisi ile derlenir.
Java As Program Languages
This bytecode is the same no matter what hardware or operating system the program is running under. There is a JIT (Just In Time) compiler within the Java Virtual Machine, or JVM.
The JIT compiler translates the Java bytecode into native processor instructions at run- time and caches the native code in memory during execution. The use of bytecode as an intermediate language permits Java programs to run on any platform that has a virtual machine available. The use of a JIT compiler means that Java applications, after a short delay during loading and once they have . Every supported operating platform has its own JVM. Class libraries. This code is typically provided as a set of dynamically loadable libraries that 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 many of the same reusable functions commonly found in modern operating systems. Most of the system library is also written in Java. For instance, the Swing library paints the user interface and handles the events itself, eliminating many subtle differences between how different platforms handle components. The Java class libraries serve three purposes within the Java platform. First, like other standard code libraries, the Java libraries provide the programmer a well- known set of functions to perform common tasks, such as maintaining lists of items or performing complex string parsing. Second, the class libraries provide an abstract interface to tasks that would normally depend heavily on the hardware and operating system.
Tasks such as network access and file access are often heavily intertwined with the distinctive implementations of each platform. The java. net and java. OS code, then provide a standard interface for the Java applications to perform those tasks. Finally, when some underlying platform does not support all of the features a Java application expects, the class libraries work to gracefully handle the absent components, either by emulation to provide a substitute, or at least by providing a consistent way to check for the presence of a specific feature. Languages. Programming languages are typically outside of the scope of the phrase . The language and runtime were therefore commonly considered a single unit. However, an effort was made with the Java 7 specification to more clearly treat the Java language and the Java virtual machine as separate entities, so that they are no longer considered a single unit.
Some of these are for existing languages, while others are for extensions to the Java language. These include: Bean. Shell . For these reasons, it is more of a transitional language to switch from Java to the . NET platform than it is a first class .
Java As Program Language Perl
NET language. Visual J# was discontinued with the release of Microsoft Visual Studio 2. The existing version shipping with Visual Studio 2. Since the introduction of Java, it has been by far the most widely used Java software development kit (SDK).
Engineer Patrick Naughton had become increasingly frustrated with the state of Sun's C++ and C application programming interfaces (APIs) and tools. While considering moving to Ne. XT, Naughton was offered. Together with other engineers, they began work in a small office on Sand Hill Road in Menlo Park, California. They aimed to develop new technology for programming next- generation smart appliances, which Sun expected to offer major new opportunities. Because they were developing an embedded system with limited resources, they decided that C++ needed too much memory and that its complexity led to developer errors. The language's lack of garbage collection meant that programmers had to manually manage system memory, a challenging and error- prone task.
The team also worried about the C++ language's lack of portable facilities for security, distributed programming, and threading. Finally, they wanted a platform that would port easily to all types of devices. Bill Joy had envisioned a new language combining Mesa and C. In a paper called Further, he proposed to Sun that its engineers should produce an object- oriented environment based on C++.
Initially, Gosling attempted to modify and extend C++ (a proposed development that he referred to as . Their first demonstration, on September 3, 1. PDA) device named Star. In November of that year, the Green Project was spun off to become Firstperson, a wholly owned subsidiary of Sun Microsystems, and the team relocated to Palo Alto, California. However, the cable industry felt that their platform gave too much control to the user, so Firstperson lost their bid to SGI. An additional deal with The 3.
DO Company for a set- top box also failed to materialize. Unable to generate interest within the television industry, the company was rolled back into Sun. Java meets the Web. They felt that with the advent of graphical web browsers like Mosaic the Internet could evolve into the same highly interactive medium that they had envisioned for cable TV. As a prototype, Naughton wrote a small browser, Web. Runner (named after the movie Blade Runner), renamed Hot.
Java. Accompanying Gage's announcement, Marc Andreessen, Executive Vice President of Netscape Communications Corporation, unexpectedly announced that Netscape browsers would include Java support. On January 9, 1. 99. Sun Microsystems formed the Java.
Soft group to develop the technology. Since J2. SE 1. 4 the Java Community Process (JCP) has governed the evolution of the Java Language.
The JCP uses Java Specification Requests (JSRs) to propose and specify additions and changes to the Java platform. The Java Language Specification (JLS) specifies the language; changes to the JLS are managed under JSR 9. Major additions included an extensive retooling of the AWT event model, inner classes added to the language, Java. Beans and JDBC. J2. SE 1. 2 (December 8, 1. This and subsequent releases through J2. SE 5. 0 were rebranded Java 2 and the version name .
Major additions included reflection, a collections framework, Java IDL (an interface description language implementation for CORBA interoperability), and the integration of the Swing graphical API into the core classes. A Java Plug- in was released, and Sun's JVM was equipped with a JIT compiler for the first time.
J2. SE 1. 3 (May 8, 2. Notable changes included the bundling of the Hot. Spot JVM (the Hot. Spot JVM was first released in April, 1. J2. SE 1. 2 JVM), Java. Sound, Java Naming and Directory Interface (JNDI) and Java Platform Debugger Architecture (JPDA).
J2. SE 1. 4 (February 6, 2. This became the first release of the Java platform developed under the Java Community Process as JSR 5. It was originally numbered 1.