A Sun Microsystems initiative to guide developers in
writing, certifying, and marketing applications written entirely in the
Java(TM) programming language.
A collection of graphical user interface (GUI) components that were
implemented using native-platform versions of the components. These
components provide that subset of functionality which is common to all
native platforms. Largely supplanted by the Project Swing component
set. See also Swing Set.
A Java(TM) programming language keyword used in a class definition to
specify that a class is not to be instantiated, but rather inherited by
other classes. An abstract class can have abstract methods that are not
implemented in the abstract class, but in subclasses.
A class that contains one or more abstract methods, and therefore can
never be instantiated. Abstract classes are defined so that other
classes can extend them and make them concrete by implementing the
abstract methods.
Application Programming Interface. The specification of how a programmer
writing an application accesses the behavior and state of classes and objects.
Networked devices such as printers, Java(TM) technology-enabled terminals, and clients, that are
managed using applications built using the Java Management API (JMAPI).
A program written in the Java(TM) programming language to run within a
web browser compatible with the Java platform, such as HotJava(TM) or
Netscape Navigator(TM).
Refers to an expression or variable that can have only a true or false
value. The Java(TM) programming language provides the boolean type and the literal values true and false.
A Java(TM) programming language keyword used to resume program
execution at the statement immediately following the current statement. If
followed by a label, the program resumes execution at the labeled
statement.
A Java(TM) programming language keyword that defines a group of
statements to begin executing if a value specified matches the value defined by a preceding "switch" keyword.
A Java(TM) programming language keyword used to declare a block of
statements to be executed in the event that a Java exception, or run time
error, occurs in a preceding "try" block.
In the Java(TM) programming language, a type that defines the
implementation of a particular kind of object. A class definition
defines instance and class variables and methods, as well as
specifying the interfaces the class implements and the immediate
superclass of the class. If the superclass is not explicitly
specified, the superclass will implicitly be Object.
A method that is invoked without reference to a particular object. Class
methods affect the class as a whole, not a particular instance of the class.
Also called a static method.
See also instance method.
A classpath is an environmental variable which tells the Java(TM)
virtual machine* and Java technology-based applications (for example,
the tools located in the JDK(TM) 1.1.X\bin directory) where to find the
class libraries, including user-defined class libraries.
A data item associated with a particular class as a whole--not with
particular instances of the class.
Class variables are defined in class definitions.
Also called a static field.
See also instance variable.
In the client/server model of communcations, the client is a process that
remotely accesses resources of a compute server, such as compute power and large memory capacity.
Works together with the code attribute in the
<APPLET> tag to give a complete specification of where to
find the main applet class file: code specifies the name of the file, and
codebase specifies the URL of the directory containing the file.
In a program, explanatory text that is ignored by the compiler. In
programs written in the Java(TM) programming language, comments are
delimited using // or /*...*/.
A program to translate source code into code to be executed by a
computer. The Java(TM) compiler translates source code written in the
Java programming language into bytecode for the Java virtual
machine*. See also interpreter.
A pseudo-method that creates an object. In the Java(TM) programming
language, constructors are instance methods with the same name as
their class. Constructors are invoked using the new
keyword.
A Java(TM) programming language keyword used to resume program
execution at the end of the current loop. If followed by a label,
"continue" resumes execution where the label occurs.
A public class (or interface) that is a standard member of the Java(TM) Platform. 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. See also, 100% Pure Java(TM).
A segment of code in which a thread uses resources (such as certain instance
variables) that can be used by other threads, but that must not be used by them
at the same time.
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.
A Java(TM) programming language keyword optionally used after all
"case" conditions in a "switch" statement. If all "case" conditions are
not matched by the value of the "switch" variable, the "default" keyword
will be executed.
A Java(TM) programming language keyword used to declare a loop that
will iterate a block of statements. The loop`s exit condition can be
specified with the "while" keyword.
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.
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.
The localization of knowledge within a module. 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.
An event during program execution that prevents the program from
continuing normally; generally, an error. The Java(TM) programming
language supports exceptions with the try, catch, and throw
keywords. See also exception handler.
A block of code that reacts to a specific type of exception. If the
exception is for an error that the program can recover from, the program can
resume executing after the exception handler has executed.
Class X extends class Y to add functionality, either by adding
fields or methods to class Y, or by overriding methods of class Y.
An interface extends another interface by adding methods. Class X is
said to be a subclass of class Y. See also derived
from.
A Java(TM) programming language keyword. 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.
A Java(TM) programming language keyword that executes a block of
statements regardless of whether a Java Exception, or run time error,
occurred in a block defined previously by the "try" keyword.
A Java(TM) programming language keyword used to declare a loop that
reiterates statements. The programmer can specify the statements to be
executed, exit conditions, and initialization variables for the loop.
The basic Internet File Transfer Protocol. FTP, which is based on TCP/IP,
enables the fetching and storing of files between hosts on the Internet.
See also TCP/IP.
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.
Graphical User Interface. 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.
The numbering system that uses 16 as its base. The marks 0-9 and
a-f (or equivalently A-F) represent the digits 0 through 15. In
programs written in the Java(TM) programming language, hexadecimal numbers
must be preceded with 0x. See also octal.
A classification of relationships in which each item except the top one
(known as the root) is a specialized form of the item above it. 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.
HyperText Markup Language. This is a file format, based on SGML, for
hypertext documents on the Internet. 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.
Interface Definition Language. APIs written in the Java(TM)
programming language that provide standards-based interoperability and
connectivity with CORBA (Common Object Request Broker Architecture).
A Java(TM) programming language keyword optionally included in the
class declaration to specify any interfaces that are implemented by the
current class.
A Java(TM) programming language keyword used at the beginning of a
source file that can specify classes or entire packages to be referred to
later without including their package names in the reference.
An object of a particular class. 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.
Any item of data that is associated with a particular object. 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.
A two-argument Java(TM) programming language keyword that tests
whether the run-time type of its first argument is assignment compatible
with its second argument.
A Java(TM) programming language keyword used to define a collection of
method definitions and constant values. It can later be implemented by
classes that define this interface with the "implements" keyword.
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.
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
TCP/IP.
A module that alternately decodes and executes every statement in
some body of code. The Java(TM) interpreter decodes and executes bytecode
for the Java virtual machine*. See also compiler, runtime
system.
JAR (Java Archive) is a platform-independent file format that aggregates
many files into one. Multiple applets written in the Java(TM) programming language, and their requisite components
(.class files, images, sounds and other resource files) can be bundled
in a JAR file and subsequently downloaded to a browser in a single HTTP
transaction. It also supports file compression and digital signatures.
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.
Sun's processor, which executes bytecode for the Java(TM) virtual
machine* natively. With a JavaChip processor, bytecode bypasses the
virtual machine or just-in-time compiler stage to go directly to the
processor.
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.
An industry standard for database-independent connectivity between
the Java(TM) platform and a wide range of databases. The JDBC(TM) provides
a call-level API for SQL-based database access.
A service designed for individual developers, providing online training,
product discounts, feature articles, bug information, and early access
capabilities.
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. Four APIs have been designed
within the Java(TM) Enterprise API family.
APIs written in the Java programming language that provide
standards-based interoperability and connectivity with CORBA (Common
Object Request Broker Architecture).
The core framework supports clocks for synchronizing between
different media (e.g., audio and video output). The standard extension
framework allows users to do full audio and video streaming.
An Java(TM) technology-based operating system that is optimized to run
on a variety of computing and consumer platforms. 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.
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.
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.
There are 3 distinct editions of the Java Platform:
* Java 2 Platform, Enterprise Edition:
The edition of the Java platform that is targeted at enterprises
to enable development, deployment, and management of multi-tier
server-centric applications.
* Java 2 Platform, Standard Edition:
The edition of the Java platform that enables development,
deployment, and management of cross-platform, general-purpose
applications.
* Java 2 Platform, Micro Edition:
The edition of the Java platform that is targeted at small,
standalone or connectable consumer and embedded devices to
enable development, deployment, and management of applications
that can scale from smart cards through mobile devices and
set-top boxes to conventional computing devices.
A distributed object model for Java(TM) program to Java program, in
which the methods of remote objects written in the Java programming
language can be invoked from other Java virtual machines*, possibly on
different hosts.
A subset of the Java Development Kit (JDK(TM)) for end-users and
developers who want to redistribute the runtime environment alone.
The Java runtime environment consists of the Java virtual machine*, the
Java core classes, and supporting files.
A Web scripting language that is used in both browsers and Web
servers. Like all scripting languages, it is used primarily to tie
other components together or to accept user input.
The first program that allows you to easily create Java(TM)
technology-based applications and applets without having to know the
Java programming language.
Sun's specification for or implementation of a software "execution
engine" that safely and compatibly executes the byte codes in Java
class files on a microprocessor (whether in a computer or in another
electronic device).
* Java HotSpot(TM) performance engine - Sun's ultra-high-performance
engine for implementing the Java runtime environment which
features an adaptive compiler that dynamically optimizes the
performance of running applications.
* KJava(TM) virtual machine - Sun's small-footprint, highly optimized
foundation of a runtime environment within the
Java 2 Platform, Micro Edition. Derived from the Java virtual
machine, it is targeted at small connected devices and can scale
from 30KB to approximately 128KB, depending on the target
device's functionality.
* Java Card(TM) virtual machine - Sun's ultra-small-footprint,
highly-optimized foundation of a runtime environment within the
Java 2 Platform, Micro Edition. Derived from the Java virtual
machine, it is targeted at smart cards and other severely
memory-constrained devices and can run in devices with
memory as small as 24K of ROM, 16K of EEPROM, and 512
bytes of RAM.
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.
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.
A user interface, built on the Java(TM) Electronic Commerce Framework,
which allows for online purchases, value transfers, and administrative
functions.
Java(TM) Database Connectivity. An industry standard for
database-independent connectivity between the Java platform and a wide
range of databases. The JDBC interface provides a call-level API for
SQL-based database access.
Sun's Jini technology includes a set of APIs that may be incorporated an
optional package for any Java 2 platform edition. 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.
Java(TM) Management API. A collection of Java programming language
classes and interfaces that allow developers to build system, network,
and service management applications.
Joint Photographic Experts Group. An image file compression standard
established by this group. It achieves tremendous compression at the cost of
introducing distortions into the image which are almost always imperceptible.
Java(TM) runtime environment. A subset of the Java Developer Kit for
end-users and developers who want to redistribute the runtime
environment. The Java runtime environment consists of the Java virtual
machine*, the Java core classes, and supporting files.
A compiler that converts all of the bytecode into native machine
code just as a Java(TM) program is run. This results in run-time speed
improvements over code that is interpreted by a Java virtual machine*.
The Java(TM) programming language sets aside words as keywords - these
words are reserved by the language itself and therefore are not available
as names for variables or methods.
A module that builds an executable, complete program from component machine
code modules. The Java(TM) linker creates a runnable program from compiled classes.
See also compiler, interpreter, runtime
system.
The basic representation of any integer, floating point, or character value.
For example, 3.0 is a double-precision floating point literal, and "a" is a
character literal.
A data item known within a block, but inaccessible to code outside
the block. For example, any variable defined within a method is a
local variable and can't be used outside the method.
A program that provides a simple GUI that enables easy access to the data
stored on the Internet. These data may be simple files or hypertext documents.
Mosaic was written by a team at NCSA.
A Java(TM) programming language keyword that is used in method
declarations to specify that the method is not implemented in the same
Java source file, but rather in another language.
The principal building blocks of object-oriented programs. Each object is
a programming unit consisting of data (instance
variables) and functionality (instance
methods). See also class.
The numbering system using 8 as its base, using the numerals 0-7
as its digits. In programs written in the Java(TM) programming language,
octal numbers must be preceded with 0. See also hexadecimal.
Using one identifier to refer to multiple items in the same
scope. In the Java(TM) programming language, you can overload methods but
not variables or operators.
Portable Operating System for UNIX(TM). A standard that defines the language
interface between the UNIX operating system and application programs through a
minimal set of supported functions.
A Java(TM) programming language keyword used in a method or variable
declaration. It signifies that the method or variable can only be accessed
by other elements of its class.
A Profile is a collection of Java APIs that complements one or more Java 2
Platform Editions by adding domain-specific capabilities. Profiles may also
include other defined Profiles. A profile implementation requires a Java 2
Platform Edition to create a complete development and deployment
environment in a targeted vertical market. Each profile is subject to
an associated set of compatibility requirements.
Profiles may be usable on one or more editions.
Some examples of profiles within the Java 2 Platform, Micro Edition are:
* PersonalJava(TM) - for non-PC products that need to display web-compatible Java-based content
* Java Card(TM) - for secure smart cards and other severely memory-constrained devices.
A Java(TM) programming language keyword used in a method or variable
declaration. It signifies that the method or variable can only be accessed
by elements residing in its class, subclasses, or classes in the same
package.
A Java(TM) programming language keyword used in a method or variable
declaration. It signifies that the method or variable can be accessed by
elements residing in other classes.
In a hierarchy of items, the one item from which all other items are
descended. The root item has nothing above it in the hierarchy. See also
hierarchy, class,
package.
The software environment in which programs compiled for the Java(TM)
virtual machine* can run. The runtime system includes all the code
necessary to load programs written in the Java programming language,
dynamically link native methods, manage memory, handle exceptions, and
an implementation of the Java virtual machine, which may be a Java
interpreter.
Comprises a number of cooperating system components, ranging from
security managers that execute as part of the application, to security
measures designed into the Java(TM) virtual machine* and the language
itself. The sandbox ensures that an untrusted, and possibly malicious,
application cannot gain access to system resources.
A characteristic of an identifier that determines where the
identifier can be used. Most identifiers in the Java(TM) programming
environment have either class or local scope. Instance and class
variables and methods have class scope; they can be used outside the
class and its subclasses only by prefixing them with an instance of
the class or (for class variables and methods) with the class
name. All other variables are declared within methods and have local
scope; they can be used only within the enclosing block.
Standardized Generalized Markup Language. An ISO/ANSI/ECMA standard that
specifies a way to annotate text documents with information about types of
sections of a document.
A Java(TM) programming language keyword used to define a variable as a
class variable. Classes maintain one copy of class variables regardless of
how many instances exist of that class. "static" can also be used to
define a method as a class method. Class methods are invoked by the class
instead of a specific instance, and can only operate on class
variables.
A Java(TM) programming language keyword used to evaluate a variable
that can later be matched with a value specified by the "case" keyword in
order to execute a group of statements.
The code name for a collection of graphical user interface (GUI)
components that runs uniformly on any native platform which supports
the Java(TM) virtual machine*. Because they are written entirely in the
Java programming language, these components may provide functionality
above and beyond that provided by native-platform
equivalents. (Contrast with AWT.)
A keyword in the Java programming language that, when applied to a
method or code block, guarantees that at most one thread at a time
executes that code.
Transmission Control Protocol based on IP. This is an Internet protocol that
provides for the reliable delivery of streams of data from one host to another.
See also IP.
A test suite, a set of tools, and other requirements used to
certify an implementation of a particular Sun technology conformant
both to the applicable specifications and to Sun or Sun-designated
reference implementations.
A Java(TM) programming language keyword that can be used to represent
an instance of the class in which it appears. "this" can be used to access
class variables and methods.
The basic unit of program execution. A process can have several threads
running concurrently, each performing a different job, such as waiting for
events or performing a time-consuming job that the program doesn't need to
complete before going on. When a thread has finished its job, the thread is
suspended or destroyed. See also process.
A Java(TM) programming language keyword used in method declarations
that specify which exceptions are not handled within the method but rather
passed to the next higher level of the program.
A keyword in the Java programming language that indicates that a
field is not part of the serialized form of an object. When an object
is serialized, the values of its transient fields are not included in
the serial representation, while the values of its non-transient
fields are included.
A Java(TM) programming language keyword that defines a block of
statements that may throw a Java language exception. If an exception is
thrown, an optional "catch" block can handle specific exceptions thrown
within the "try" block. Also, an optional "finally" block will be executed
regardless of whether an exception is thrown or not.
Uniform Resource Locator. A standard for writing a text reference
to an arbitrary piece of data in the WWW. A URL looks like
"protocol://host/localinfo" where protocol specifies a protocol to use
to fetch the object (like HTTP or FTP), host specifies the Internet
name of the host on which to find it, and localinfo is a string (often
a file name) passed to the protocol handler on the remote host.
An abstract specification for a computing device that can be
implemented in different ways, in software or hardware. You compile
to the instruction set of a virtual machine much like you'd compile to
the instruction set of a microprocessor. The Java(TM) virtual machine*
consists of a bytecode instruction set, a set of registers, a stack, a
garbage-collected heap, and an area for storing methods.
A Java(TM) programming language keyword used in method declarations to
specify that the method does not return any value. "void" can also be used
as a nonfunctional statement.
A Java(TM) programming language keyword used in variable declarations
that specifies that the variable is modified asynchronously by
concurrently running threads.
A Java(TM) programming language keyword used to declare a loop that
iterates a block of statements. The loop`s exit condition is specified as
part of the while statement.
Files on a file system that can be viewed (read) by any user. For example:
files residing on web servers can only be viewed by Internet users if their
permissions have been set to world readable.
