String — an instance of an immutable String class, containing zero or more Unicode characters:. Unicode — a bit character set defined by ISO , designed to make exchange and display of information easier across various languages. You can read more about the difference between these two concepts here.
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Start Free Trial. About the Author Latest Posts. Also called a static field. See also instance variable. In the current implementation of the Java TM platform, the compilation unit is a file. See also interpreter. In the Java TM programming language, constructors are instance methods with the same name as their class.
Constructors are invoked using the new keyword. However, it is not used by current versions of the Java programming language. If followed by a label, "continue" resumes execution where the label occurs.
The intent is that the core classes for the Java platform, at minimum, are available on all operating systems where the Java platform runs. A program written entirely in the Java programming language relies only on core classes, meaning it can run anywhere. Core Packages The required set of APIs in a Java platform edition which must be supported in any and all compatible implementations. D declaration A statement that establishes an identifier and associates attributes with it, without necessarily reserving its storage for data or providing the implementation for methods.
See also definition. If all "case" conditions are not matched by the value of the "switch" variable, the "default" keyword will be executed. See also declaration. See also subclass , superclass. See also single precision. E else A Java TM programming language keyword used to execute a block of statements in the case that the test condition with the "if" keyword evaluates to false.
EmbeddedJava TM Technology The availability of Sun's Java 2 Platform, Micro Edition technology under a restrictive license agreement that allows a licensee to leverage certain Java technologies to create and deploy a closed-box application that exposes no APIs.
Because objects encapsulate data and implementation, the user of an object can view the object as a black box that provides services.
Instance variables and methods can be added, deleted, or changed, but as long as the services provided by the object remain the same, code that uses the object can continue to use it without being rewritten. See also instance variable , instance method. The Java TM programming language supports exceptions with the try, catch, and throw keywords.
See also exception handler. If the exception is for an error that the program can recover from, the program can resume executing after the exception handler has executed. See also applet. An interface extends another interface by adding methods. Class X is said to be a subclass of class Y. See also derived from.
Unless specified otherwise, a field is not static. You define an entity once and cannot change it or derive from it later. More specifically: a final class cannot be subclassed, a final method cannot be overridden and a final variable cannot change from its initialized value.
The programmer can specify the statements to be executed, exit conditions, and initialization variables for the loop. See also actual parameter list. G garbage collection The automatic detection and freeing of memory that is no longer in use. The Java TM runtime system performs garbage collection so that programmers never explicitly free objects.
Refers to the techniques involved in using graphics, along with a keyboard and a mouse, to provide an easy-to-use interface to some program. H hexadecimal The numbering system that uses 16 as its base.
The marks and a-f or equivalently A-F represent the digits 0 through In programs written in the Java TM programming language, hexadecimal numbers must be preceded with 0x. See also octal. Each item can have one or more items below it in the hierarchy. In the Java TM class hierarchy, the root is the Object class. It is very simple and allows for the embedding of images, sounds, video streams, form fields and simple text formatting.
References to other objects are embedded using URLs. See also superclass , subclass. In programs written in the Java TM programming language, an instance of a class is created using the new operator followed by the class name. Also called simply a method. See also class method. Each instance of a class has its own copy of the instance variables defined in the class. Also called a field. See also class variable. It can later be implemented by classes that define this interface with the "implements" keyword.
Internet An enormous network consisting of literally millions of hosts from many organizations and countries around the world. It is physically put together from many smaller networks and data travels by a common set of protocols. IP Internet Protocol. The basic protocol of the Internet. It enables the unreliable delivery of individual packets from one host to another.
It makes no guarantees about whether or not the packet will be delivered, how long it will take, or if multiple packets will arrive in the order they were sent. Protocols built on top of this add the notions of connection and reliability. See also compiler , runtime system. JAR Files. A file format used for aggregating many files into one. Multiple applets written in the Java TM programming language, and their requisite components.
It also supports file compression and digital signatures. Java TM Sun's trademark for a set of technologies for creating and safely running software programs in both stand-alone and networked environments. JavaBeans TM A portable, platform-independent reusable component model. Java Blend TM A product that enables developers to simplify database application development by mapping database records to objects in the Java TM programming language Java objects and Java objects to databases.
JavaCheck TM A tool for checking compliance of applications and applets to a specification. With a JavaChip processor, bytecode bypasses the virtual machine or just-in-time compiler stage to go directly to the processor. Java TM Compatibility Kit JCK A test suite, a set of tools, and other requirements used to certify a Java platform implementation conformant both to the applicable Java platform specifications and to Java Software reference implementations.
Java Developer Connection SM A service designed for individual developers, providing online training, product discounts, feature articles, bug information, and early access capabilities. Java TM Enterprise API This API makes it easy to create large-scale commercial and database applications that can share multimedia data with other applications within an organization or across the Internet. Java TM Media Framework The core framework supports clocks for synchronizing between different media e.
The standard extension framework allows users to do full audio and video streaming. The JavaOS TM operating environment provides a runtime specifically tuned to run applications written in the Java programming language directly on hardware platforms without requiring a host operating system. Java TM Platform Consists of a language for writing programs "the Java TM programming language" ; a set of APIs, class libraries, and other programs used in developing, compiling, and error-checking programs; and a virtual machine which loads and executes the class files.
In addition, the Java platform is subject to a set of compatibility requirements to ensure consistent and compatible implementations. Implementations that meet the compatibility requirements may qualify for Sun's targeted compatibility brands.
The Java TM 2 platform is the current generation of the Java platform. Java TM Platform Editions A Java platform "edition" is a definitive and agreed-upon version of the Java platform that provides the functionality needed over a broad market segment. An edition is comprised of two kinds of API sets: i "core packages," which are essential to all implementations of a given platform edition, and ii "optional packages," which are available for a given platform edition and which may be supported in a compatible implementation.
Like all scripting languages, it is used primarily to tie other components together or to accept user input. Java Studio TM The first program that allows you to easily create Java TM technology-based applications and applets without having to know the Java programming language.
Java TM Technologies A set of technologies that enable the creation and safe running of software programs in both stand-alone and networked environments. Derived from the Java virtual machine, it is targeted at small connected devices and can scale from 30KB to approximately KB, depending on the target device's functionality. Java Web Server TM The easy-to-use, extensible, easy-to-administer, secure, platform-independent solution to speed and simplify the deployment and management of your Internet and Intranet Web sites.
It provides immediate productivity for robust, full-featured, Java technology-based server applications. Java Workshop TM A complete set of tools integrated into a single environment for managing programming with Java technology. The Java Workshop software uses a highly modular structure that enables you to easily plug new tools into the overall structure. JavaSpaces TM A technology that provides distributed persistence and data exchange mechanisms for code in the Java TM programming language.
An industry standard for database-independent connectivity between the Java platform and a wide range of databases. A software development environment for writing applets and application in the Java programming language. This set of APIs enables transparent networking of devices and services and eliminates the need for system or network administration intervention by a user.
The Jini technology is currently an optional package available on all Java 2 platform editions. A collection of Java programming language classes and interfaces that allow developers to build system, network, and service management applications. A set of APIs that assist with the interfacing to multiple naming and directory services. An image file compression standard established by this group.
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