Java Glossary

8/6/2019 Java Glossary

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Glossary

abstract class:A class that is uninstantiable. That is, you cannot instantiate/generate any objectsfrom this class. Abstract classes may have both concrete and abstract methods, the

latter methods declared only with their signature without any code/implementation.The intention is for all derived (inherited) classes to provide a definition, makingthe method polymorphic.

abstraction:A term applied to the process of hiding unimportant details in favor of those thatmatter. Function and data abstraction are tools employed in software engineering tohandle complexity.

activity diagram:UML notation is used for showing the objects' connection with workflow and

describing the operations in parallel processing. There is one activity diagram foreach use case.

actor:In UML, a role that a user plays when interfacing with the application. The actordoes not have to be a user, it can be another system that interfaces with theapplication. A single actor can perform many use cases.

aggregation:The combining of data and behavior within an object.

anchor:A part of a hypertext document that is either the source or destination of a hypertextlink. A link might extend from an anchor to another document, or from anotherdocument to an anchor. When anchors are the starting points of these links, they aretypically highlighted or otherwise identified in the hypertext browser as hotspots.

applet:A Java(TM) application program that can be included in a Hypertext MarkupLanguage page via the element (or tag) and can be observed in a Javatechnology-enabled browser or applet viewer.

applet parameter:Arguments passed to Java(TM) technology applets. Parameters are defined withinthe Hypertext Markup Language (HTML) element (or tag) and denoted by the wordPARAM.

Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.


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applet viewer:Any program capable of executing Java(TM) technology applets; for example,Netscape Navigator(TM) 2.0 or higher and the HotJava(TM) browser.

appletviewer:

The appletviewer command allows you to run applets outside the context of aWorld Wide Web browser. The command reads in a Hypertext Markup Language(HTML) document and displays each applet referenced in its own window.

application:An application is a term that generically refers to any program executable by acomputer.

argument:An argument is a value or data passed from one program (or part of) to another. Inthe Java programming language, arguments are typically used with methods.

ASCII:The American Standard Code for Information Interchange (ASCII) character set isthe predominant character set encoding of present-day computers. The modernversion uses 7 bits for each character, whereas most earlier codes (including anearly version of ASCII) used fewer. This change allowed the inclusion of lowercaseletters, but it did not provide for accented letters or any other letterforms not used inEnglish (such as the German sharp-S or the ae-ligature that is a letter in, forexample, Norwegian).

association:A term that describes an object that is associated with another when it "uses" theother for some purpose. This is a flexible object relationship, in which theassociation can be made and broken at any time. A Person object may be associatedwith a Book object, then another Book object. The lifetimes of the objects need onlyintersect.

attribute:A property of an Hypertext Markup Language (HTML) element, specified in thestart tag of the element. The attribute list of the element is used to pass values to theJava (TM)technology program defining the applet.

attribute (HTML):

A property of an Hypertext Markup Language (HTML) element. For example, theAPPLET tag uses the tag to pass attributes to the Java(TM) technology programdefining the applet.



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attribute (object):The data or state of objects. Two objects of the same class can differ by the valuestheir attributes hold, but the types of the attributes remain the same, as defined inthe class.

automatic variable:An automatic variable is created when execution enters a method and is destroyed atexit from the method. This is why automatic variables are sometimes referred to as"temporary" or "stack" variables.

behavior:

Behavior is the way that an object acts or reacts by changing its data or byinteracting with other objects.

binary semaphore:A semaphore is a flag (in this case an integer variable) which is used to controlaccess to a piece of data. Before using it, a process must check the value. If it isgreater than 0, the process decrements the counter, uses the data, then incrementsthe counter. A binary is either available or not; its value can either be 0 or 1.

boolean:A boolean is a primitive data type represented by a value of either true or false.

browser:A browser is a software program for observing a synonym for a Web client.

Byte:

An 8-bit primitive integral type used to store whole numbers in the range -2^7 to2^7 -1. See also integral types.

bytecode:Any Java virtual machine compliant code that is created as the result of compiling aJava programming language source code file is called a bytecode. Bytecodes arearchitecture neutral and easily distributed across networks. A browser or otherapplication that implements a Java virtual machine can interpret bytecode.



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C++:C++ is one of the most widely used object-oriented languages, a superset of Cdeveloped primarily by Bjarne Stroustrup at AT&T BellLaboratories in 1986.In C++, a class is a user-defined type, syntactically a structurewith member functions. Constructors and destructors are member functions called

to create or destroy instances. A friend is a nonmember function that is allowed toaccess the private portion of a class. C++ allows implicit type conversion, functioninlining, overloading of operators and function names, and default functionarguments. It has streams for I/O and references.C++ 2.0 (May 1989) introducedmultiple inheritance, type-safe linkage, pointers to members, and abstract classes.

casting:As used in programming, casting changes an expression or an object from one datatype to another.

CERN:Centre European pour la Recherche Nucleaire (CERN) is the European laboratoryfor particle physics where the World Wide Web originated in 1989.

CGI:The common gateway interface (CGI) is a standard for programs to interface withWeb servers.

char:A primitive textual type used for storing a single character.

child class:A child class is a subclass of class (its parent class. It inherits public (and protected)data and methods from the parent class.

class:The term class defines the classification of a group of related objects. A classprovides a blueprint, defines behaviorand (data) data for all instantiated objects. For example, a class Person defines thecommon behavior and attributethat objects (instances) instance of the Person class will possess.

class diagram:Describes the objects in an application and the relationships between those objects.

It also shows the attributes (object)operations of the classes.

client:The work client refers to a software application that receives information or servicesfrom a server.



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Collection:Used to contain collections of other objects. The behavior of the collection reflectsthe organizational structure required when grouping the objects. For example, a listcollection class organizes objects into a list, a tree collection class organizes objectsinto a tree.

compiler:A compiler is a software program that translates human-readable source code intomachine-executable code.

composition:The term composition defines the object relationship of "has a" or "aggregation". Itis useful when one object contains another for the duration of its life and itscomponent's life. For example, a Person object contains a Heart object; both arecreated together and destroyed together. Composition is less flexible thanassociation, but it removes the need to manage explicitly the creation anddestruction of the components.

constant:A constant is a data item whose value does not change.

constant_association:This term describes an association that lasts for the lifetime of the associate. Forexample, a lens may be constantly associated with a frame to produce a spectacleobject. Only when the lifetime of the lens ends (because it breaks or is no longercorrect) does the association end. At this time, another lens may be constantlyassociated with the frame. The relationship models the fact that the lens wouldnever be used in another frame.

constructor:A constructor is a special method-like member of a class. A constructor is invokedwhen an object of that class isinstantiated, and is used to initialize the object.

content handler:A program loaded into the user's browser that interprets files of a type defined bythe Java(TM) technology programmer. The Java(TM) technology programmerprovides the necessary code for the user's browser to display and interpret thisspecial format.

CORBA:Common Object Request Broker Architecture (CORBA) is a specification put forthby Object Management Group (OMG) for creating, distributing, and managingdistributed objects in a network.



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custody:Relates to object ownership, and concerns the right to destroy the object. An objectwith custody of another is responsible for destroying the other. For example, whileBook objects are associated with a Library object, the Library may hold custody. If the Library burns down, the Books are destroyed; however, Books on loan are

preserved because they are in the custody of Person objects. Determining wherecustody lies is an important part of object modeling.

data:

The information contained in, or the current state of, an object.

delegation:Delegation is a object-oriented behavior that allows one object to pass a message (or"delegate the message") to an object embedded within the former object. Forexample, a Window object can be designed to contain a Rectangle object; amessage to get the window's area would be delegated to the method that implementsthe area calculation for the rectangle contained in that window.

deployment descriptor:The deployment descriptor contains the instructions provided by a developer to theEnterprise JavaBeans (EJB) server for managing the EJB components. It can specifyaspects, such as the transactionl behavior, security, and life cycle of thecomponents. At runtime, the container refers to the values specified in thedeployment descriptor file, initializes and performs the required operations.

document type definition:A specification for a markup language such as Hypertext Markup Language(HTML) or Standard Generalized Markup Language (SGML).

domain name:The name assigned to a group of systems on a local network that shareadministrative files is a domain name. The domain name is required for the network information service database to work properly.

double:A 64-bit Java programming language,primitive type is used to store numbers withvalues to the right of the decimal point. See also floating point types.



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dynamic binding:With dynamic binding, a reference is not associated with a particular class untilruntime - when the application is actually executed. In the Java programminglanguage, this means that a reference variable can actually point to an object from adifferent class than it was originally declared as, instead of being bound to the

declared class at compile time.

element:An element is a unit of structure in an Hypertext Markup Language (HTML)document. Many elements have start and stop tags. Some have a single tag. Someelements can contain other elements.

encapsulation:Encapsulation refers to controlling access to data and operations for callers outsidethe class.

exception:An exception in the Java programming language is an object which is instantiatedwhen an unusual flow occurs in code.Exception objects are generally derived from the Exception class, which provides astring field to describe the error. The concept of exceptions in the Javaprogramming language is the try-catch-finally sequence. Java executes a protectedcode block that might throw one or more exceptions, it can catch the exception; andfinally clean up from either the normal code path or the exception code path,whichever actually happened.

float:

A 32-bit Java programming languate primitive type used to store numbers withvalues to the right of the decimal point. See also floating point types.

floating point types:Java programming language primitive types, float and double(64-bit), used to storenumbers with values to the right of the decimal point. It is not possible to state thelargest or smallest value that each of these can hold because they allow variableaccuracy depending on the magnitude of the number.

FTP:

File Transfer Protocol (FTP) is a means to exchange files across a network.



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garbage collector:The process by which memory allocated for objects in a program is reclaimed.. TheJava programming language automatically performs this process.

generalization:

The idea of using parent classes to define the common data and behavior for anysubclasses is called generalization.See inheritance for more information.

gopher:A protocol for disseminating information on the Internet by using a system of menus.

heap:

A heap is an area of memory used for dynamic memory allocation where blocks of memory are allocated and freed in an arbitrary order, and the pattern of allocationand size of blocks is not known until runtime. Typically, a program has one heapthat it may use for several different purposes. A heap is required by languages inwhich functions can return arbitrary data structures or functions with free variables.

home page:The initial or introductory page of a World Wide Web site.

hot spot:An area on a hypertext document that a user can click on to retrieve anotherresource or document.

HotJava:

A (World Wide Web) browser, developed by Sun, that uses the programminglanguage. The HotJava browser provides the ability to import code fragments,called applets, across the Internet and execute them.

HTML:Hypertext Markup Language (HTML) is the mechanism used to create Web pages.A Web browser displays these pages according to a browser-defined renderingscheme.

HTML tag:The format codes used to mark specific elements in an HTML file. For example, the

TITLE element has a start tag, and an end tag, .

HTTP:Hypertext Transfer Protocol (HTTP) is the native protocol of the Web, which isused to transfer hypertext documents.



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hypermedia:Hypertext that includes multimedia - text, graphics, images, sound, and video.

hypertext:A collection of documents that contain cross-references (links) from one section of

a document to any other section in the same or another document. These links allowfor non-linear navigation. Web-based hypertext documents are not constrained to asingle server.

IDL:

Interface Definition Language (IDL) lets a program written in one languagecommunicate with another program written in a different language.

IIOP:Internet Inter-ORB Protocol (IIOP) is a standard network protocol that allowsinteroperability among different products from different vendors.

image map:A graphic in-line image on an Hypertext Markup Language (HTML) page thatpotentially connects each pixel or region of an image to a Web resource. When themouse cursor is on certain regions of the image, clicking the mouse retrieves theresources.

information hiding:When implementing encapsulation programmers can define some parts of theprogram as visible (public)and other parts hidden (private).

inheritance:The process by which a new class (the child or subclass) is derived from an existingclass (the base, parent, or superclass). It is a central concept in object-orientedsystems and enables the reuse of the base class members. During class inheritance,the derived class may extend or override members inherited from the base class.

instance:An object.

instruction set:

An instruction set is the "programmer-visible" portions of a processor's architecture,such as the machine language instructions and registers. Parts of the architecturethat are left to the implementation, such as number of superscalar functional units,cache size, and cycle speed, are not part of the instruction set architecture (ISA).



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int:A 32-bit primitive integral type used to store whole numbers in the range -2^31 to2^31 -1. See also integral types.

integral types.:

A category of primitive types in the Java programming language used to storepositive or negative whole numbers. The four integral types are:byteshortint, andlong

interface:The set of public functions that an object makes available to the system. In Java, aninterface defines a set of public methods that all implementing classes sign acontract to implement. Interfaces should be designed to be as small as possible(minimizing coupling) and should capture the essence and behavior of what is beingmodeled.

Internet:The Internet is the largest network in the world. It consists of a large nationalbackbone network that contains the Military Network (MILNET), the NationalScience Foundation Network (NSFNET), and the European Laboratory for ParticlePhysics (CERN), and a myriad of regional and local campus networks all over theworld. The Internet uses the Transmission Control Protocol/Internet Protocol(TCP/IP) suite. To be able to log on to the Internet the user must have InternetProtocol (IP) connectivity; that is, be able to communicate with other systems byusing telnet or ping. Networks with only email connectivity arenot classified as being on the Internet.



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interpreter:An interpreter is a program that executes other programs. This is in contrast to acompiler that does not execute its input program (the source code) but translates itinto executable machine code (also called object code) that is output to a file forlater execution. It might be possible to execute the same source code either directly

by an interpreter or by compiling it and then executing the machine code produced.It takes longer to run a program under an interpreter than to run the compiled codebut it can take less time to interpret it than the total time required to compile and runit. This is especially important when prototyping and testing code where an edit-interpret-debug cycle can often be much shorter than anedit-compile-run-debug cycle. Interpreting code is slower than running the compiledcode because the interpreter must analyze each statement in the program each timeit is executed and then perform the desired action, whereas the compiled code justperforms the action. This run time analysis is known as interpretiveoverhead. Access to variables is also slower in an interpreter because themapping of identifiers to storage locations must be done repeatedly at runtime ratherthan at compile time.

J2EE:

Java 2 Enterprise Edition (J2EE) is a specification that consists of a comprehensiveset of technologies to facilitate the building of distributed component-basedbusiness applications.

Java Beans:A JavaBeans component is a reusable software component that works with Java(TM) technology. More specifically, a JavaBeans component is a reusable softwarecomponent that can be visually manipulated in builder tools. The primary purposeof JavaBeans components is to enable the visual construction of applications.

Java programming language:Created by Sun, the Java programming language is an object-oriented programminglanguage for creating distributed, executable applications for a variety of computerplatforms.

Java technology application:A Java(TM) technology program that does not require an applet viewer to execute.

Java technology block:

The code between matching curly braces { and }.

Java technology package:A set of classes with a common high-level function declared with the packagekeyword.



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Java technology transaction API:Java(TM) technology transaction API (JTA) provides a programming interface tostart transactions, join existing transactions, commit transactions, and roll back transactions.

Java technology-enabled browser:A World Wide Web browser that can display Java applets.

Java transaction technology service:Java transaction service (JTS) is the Java(TM) technology binding of CommonObject Request Broker Architecture (CORBA) Object Transaction Service (OTS).

Java Virtual Machine(JVM):Java Virtual Machine (JVM) is a specification that defines an abstract machine thatacts as an interface between the compiled Java code and the hardware platform.After a JVM has been provided for a platform, any compiled Java(TM) technologyprogram can run on that platform.

Java(TM) technology applet:A Java(TM) technology program that can be included in an Hypertext MarkupLanguage (HTML) page via the element (or tag) and can be observed ina Java(TM) technology-enabled browser or applet viewer.

layout manager:

The layout manager determines how portions of the screen will be sectioned andhow components within that section will be placed. There are five basic layoutmanagers: FlowLayout, GridLayout, BorderLayout, CardLayout, andGridBagLayout.

lifetime:The time between an object's creation and its destruction. An object may have afinite lifetime in a system. When an object is composed of other objects, theirlifetimes completely overlap. When an object is associated with another object, theirlifetimes need only intersect. In the case of the latter, the programmer must addressthe issue of custody.

link:A location within a Web page that can be clicked on, taking the user to another

page, image, or other resource. A link may also point to another location within thesame page.

logical_type:See boolean.



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long:A 64-bit primitive integral type used to store whole numbers in the range -2^63...2^63-1. See also integral types.

member:The operations and the attributes (public or private) that comprise an object.

member variable:Member variables, also known as attributes, are created when an object isconstructed using the new Xxxx() call. These variables continue to exist for as longas the object exists.

memory allocation-deallocation:When a program declares a variable, memory sufficient to contain valid values of the variable is automatically reserved (allocated). When this variable is no longerneeded the reserved memory is released (deallocated).Many languages allow the programmer to explicitly allocate memory and explicitlydeallocate memory. A pointer variable is used to store the starting address of thememory allocated. Improper allocation/deallocation can lead to memory leaks.

memory leaks:A memory leak occurs when allocated memory is not deallocated when it is nolonger needed. As this allocation/non-deallocation process repeats, the amount of free memory decreases, hence the term "memory leak."

message passing:The activity of one object communicating with another by sending it a message.The mechanism for message passing might be as simple as a method call, but theresult is the same. Messages consist of three components: the name of the targetobject, the method being requested, and the arguments for the method, if required.

method:The behavior that an object may perform. Operations are defined in the class andmay be public (being interface functions or methods) or private (implementation).

methods:The function or behavior that an object can perform. Operations are defined in theclass and can be public (interface functions or methods) or private

(implementation).

MIME:Multimedia Imbedded Mail Extensions (MIME) is a specification for multimediadocument formats.



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Mosiac:A graphical Web browser originally developed by the National Center forSupercomputing Applications (NCSA). It now includes a number of commerciallylicensed products.

multiple inheritance:The process of deriving a new class from two or more base classes throughinheritance. The Java programming language does not support multiple inheritance.

native methods:

Class methods that are declared in a Java(TM) technology class but implemented inother programming languages, such as C.

native2ascii:The native2ascii tool converts a file with native-encoded characters (characters thatare non-Latin 1 and non-Unicode) to one with Unicode-encoded characters.The Java(TM) technology compiler and other Java(TM) technology tools can onlyprocess files that contain Latin-1 and/or Unicode-encoded (\udddd notation)characters. native2ascii converts files that contain other character encodings intofiles containing Latin-1 and/or Unicode-encoded charaters. If output file is omitted,standard output is used for output. If, in addition, input file is omitted, standardinput is used for input.

navigating:The act of observing the content of the Web for some purpose.

non-visual component:Non-visual components do not have a visual interface and are completely invisibleat run time.

object:

An instance of a class. The class specifies the form and nature of an object, and theobject is an actual instantiation of this form and nature. A class Person describesoperations and states for persons in general. Dave, John, and Jim are actual objectsof Person.

object modeling:

The process of representing a real- or problem-world scenario in terms of objects,classes, and their interrelationships.



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object oriented:The basic concept in this approach is that an "object" is a data structure (abstractdata type) encapsulated with a set of routines, called methods, that operate on thedata. Operations on the data can only be performed using these methods, which arecommon to all objects that are instances of a particular "class" (see inheritance).

Thus the interface to objects is well defined, and allows the code implementing themethods to be changed as long as the interface remains the same.Each class is a separate module and has a position in a "class hierarchy." Methodsor code in one class can be passed down the hierarchy to a subclass or inheritedfrom a superclass.Procedure calls are described in terms of message passing. A message names amethod and can, optionally, include other arguments. When a message is sent to anobject, the method is looked up in the object's class to find out how to perform thatoperation on the given object. If the method is not defined for the object's class, it islooked for in its superclass and so on up the class hierarchy until it is found or thereis no higher superclass.Procedure calls always return a result object, which might be an error, as in the casewhere no superclass defines the requested method.

objects:Objects are runtime representations or instantiations of their class definition. A classPerson describes operations andstates for people in general. Dave, John, and Jim are actual objects of Person.

OMG:Object Management Group (OMG) was an association of vendors formed in 1989to put forth a standard architecture for distributed objects. The standard architectureput forth by OMG is Common Object Request Broker Architecture (CORBA).

operations:A function or behavior that acts upon data.

ORB:Object Request Broker (ORB) is a distributed paradigm model that combinesclient/server technology with object-orientation. ORB allows business logiccomponents to be built as a series of reusable objects that can be distributed acrossmultiple platforms.

overloading:

To declare one or more methods with the same name but distinct argument lists.Java programming language methods can be overloaded.



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override:Overridding a method is replacing the superclass implementation of a method witha subclass specific one. Unlike overloading, in overriding the method signatures,including the argument list, must be identical. Note that only non-static methodsmay be overridden.

An overriden method (the implementation in the sublcass) is executed at runtimebased on the true type of the object because methods in the Java programminglanguage are virtual by design.

ownership:See custody.

package:

A package is a group of classes that belong together. Classes in a different packageneed to be imported if not already included in the classpath.For example, Java(TM) technology provides packages, such as java.io and

java.lang, which holds some of the basic classes such as System and String. Userstypically define their own package structure and group related classes together.

packet:The smallest unit of information that is usually transmitted over a network.. Apacket also contains the necessary addressing data for it to reach its destination.

page:The basic unit of information used on the World Wide Web. A Web browsergenerally views information one page at a time.

panel:An invisible GUI component used to contain other components.

parameter:See applet parameter.

parameter list:The set of values passed to a method. The definition of the method describes howthese values are manipulated.

parent class:

The originating class of a given subclass.



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pointer:A pointer is a special variable that holds a memory address. The value of the pointervariable is assigned/used inmemory allocation/deallocation routines.

pointer arithmetic:Pointer arithmetic is the process of manipulating the value stored in the pointer toaccess different parts of memory. If an error occurs, the pointer could be pointing toa location in memory that contains garbage. In Java, manipulating pointer arithmeticis not the developer's responsibility.

polymorphism:A method that is "multiply formed." That is, the same method name with the sameprototype is defined for two or more classes. Polymorphic methods have the samesemantics (that is, to read, write, display, and update an object), but differentimplementations. Each implementation is appropriate for the particular class forwhich it is defined.

primitive types:Categories of data that restrict the values you can put into a variable or that aconstant can have, and make up the simple data parts of the Java programminglanguage. Some can store only whole numbers (integral types), while others canstore decimal places as well (floating point types).Others for storing character information (char) and true/false logical values(boolean). The Java programming language rules require that you give each variableand constant a type.

primitive variable:A Java (TM)technology variable with a primitive type.

private:Members of an object that may not be accessed directly by other objects. They mayonly be accessed indirectly through public members.

problem domain:The system you want to model using OO in preparation for representing in anapplication written in the Java programming language. A problem domain could bean intersection with a traffic light, a company's system for processing orders, and soon.

protocol handler:A program that is loaded into the user's browser and that interprets a protocol. Theseprotocols include standard ones such as Hypertext Markup Language (HTTP) orprogrammer-defined protocols.



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public:Members of a class that may be accessed from other objects and other memberfunctions directly. Public member functions (data is usually private) define theinterface or methods for the class.

reference type:The type of data that can be stored in a reference variable.

reference variable:When you create objects you store them in a separate part of memory, but you needto remember the address of where they were created. Reference variables are used tohold the addresses of objects. (The object is itself defined by one of the Java(TM)technology reference types.

robot:A software program that automatically explores the Web for a variety of purposes.Robots that collect resources for later database queries by users are sometimescalled spiders.

scope:

The range over which an action or definition applies. An identifier's scope is wherethe identifier can be referenced in a program. Some identifiers can be referencedthroughout a program, while others can be referenced from only limited portions of a program. The access control modifier (public, private, protected) used in thedeclaration and where an identifier is declared determine the scope of an identifier.

semantic gap:The distance between the problem world and the computer representation of theproblem. A strength of object-oriented systems is that they reduce the semantic gapbetween the problem world and the computer representation. The entities in theproblem world are modeled directly as objects in the analysis, design, and programrepresentations. This promotes ease of understanding, verification, andmodification.

sequence diagram:UML notation used to capture the operations of a single use case and show howgroups of objects collaborate on those operations. A UML diagram showing the

sequence of interactions among objects.

server:A software application that provides information or services based on requests fromclient programs.



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SGML:Standardized, Generalized Markup Language (SGML) is an InternationalOrganization for Standardization (ISO), American National Standards Institute(ANSI), and European Computer Manufacturers Association (ECMA) standard thatspecifies a way to annotate text documents with information about types of sections

of a document; for example, "this is a paragraph" or "this is a title." short:

A 16-bit primitive integral type used to store whole numbers in the range -2^15 ...2^15 -1. See also integral types.

signature:The combination of a method's name and argument list is know as the methodsignature. In the Java programming language, it is permitted to have severalmethods in a class of the same name. Methods with the same name may have beenoverloaded (different argument list) or overriden (same signature). See alsooverloading.

site:A location on the Internet that contains a common grouping of files or information.For example, a Web site, a Gopher site, or a File Transfer Protocol (FTP) site.

smalltalk:Smalltalk is the pioneer object-oriented programming system developed by theSoftware Concepts Group, led by Alan Kay, at Xerox PARC in 1972. It includes alanguage (usually interpreted), a programming environment, and an extensive objectlibrary.Smalltalk took the concepts of class and message from Simula-67 and made themall-pervasive. Innovations included the bitmap display, windowing system, and useof a mouse.

socket:Socket is a Berkeley Software Distribution (BSD) system call used to create UNIX(R) domain sockets (the end points of communication links between processes).Because of the popularity of the BSD programming model, the name has beenreused in other areas, including Java technology.

software components:Software components are defined as reusable software building blocks that can be

assembled to create applications.

specialization:See inheritance.



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spider:A software program that traverses the Web collecting information about resourcesfor later queries by users seeking to find resources.

spoof:

"Spoof" is a technical term meaning "hoax." stack:

A stack is a data structure for storing items that are to be accessed in last-in first-outorder (LIFO). Typical operations on a stack are to create a new stack, to "push" anew item onto the top of a stack, and to "pop" the top item off. Error conditions areraised by attempts to pop an empty stack or to push an item onto a stack that has noroom for further items (because of its implementation).Most processors include support for stacks in their instruction set architectures.Perhaps the most common use of stacks is to store subroutine arguments and returnaddresses. This is usually supported at the machine codelevel directly by "jump to subroutine" and "return from subroutine" instructions, byauto-increment and auto-decrement addressing modes, or both.These allow a contiguous area of memory to be set aside for use as a stack andallow the user to choose either a special purpose register or a general purposeregister as a stack pointer.

state:The set of current data for an object. An object's state changes at runtime based onthe behaviour invoked due to interaction with other objects.

strings:The class used to store reference variables for textural values. In Java, Strings areobjects and thus have attributes as well as methods that can be invoked on them.See also reference variables.

subclass:The class that inherits from another class. Inheritance is a mechanism for defining anew class in terms of an existing class. For instance, a general Ball class could beused to define a new class, TennisBall. TennisBall inherits members from the Ballclass, so TennisBall is a subclass of the Ball superclass. See also inheritance.

subtype:UML term for subclass.



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superclass:The class that another class inherits from. Inheritance is a mechanism for defining anew class in terms of an existing class For instance, a general Ball class could beused to define a new class, TennisBall. TennisBall inherits members from the Ballclass, so TennisBall is a subclass of the Ball superclass. See also inheritance.

supertype:UML term for superclass.

surfing:The act of navigating the Web, typically by using techniques for rapidly traversingthe Web to find subjectively valuable resources.

tag:

See HTML Tag.

TCP/IP:The Transmission Control Protocol/Internet Protocol (TCP/IP) suite is used toestablish a connection for data transmission (TCP) and to define the composition of the packet of information being transferred (IP). The Internet suite is commonlyreferred to as TCP/IP. The SunOS networks run on TCP/IP by default.

text editor:A program that creates and modifies text files normally using the ASCII formatstandard.

textual type:

See char.

thread:A single-threaded program is a program that only does one task at one time. Amulti-threaded program executes more than one task at a time with concurrentthreads (contexts of execution).For example, a multi-threaded program allows you to continue working while theprogram prints in the background.Each thread is an independently executable piece of code.

typecast:

To lower the range of a value by changing its type, such as converting a long to anint. Typecasting is typically done in order to access other developer's methods thataccept only certain types as arguments, or to save memory.



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UML:Unified Modeling Language (UML) is used to model, design and notate a system inpreparation for development. UML is programming language independent and canbe used to create case, class, sequence, activity diagrams and more.

Unicode:A character set that supports many world languages. Java uses a unicode characterscheme and thus supportsinternationalization by default.

URL:A Uniform Resource Locator (URL) is a form of addressing typically used forWorld Wide Web or Internet resources.

use case:In UML, an interaction of a user with an application in order to achieve a desiredresult. A use case is a detaileddescription of a single activity in a business process that may identify actors, datainputs and outputs, performance/timing requirements, main/alternate flows,handling of error conditions and interfaces with external applications.

use case diagram:UML notation showing all the use_case for the application you want to create, theactors (a role that a user plays when interfacing with the application) on those usecases, and the links (relationships) among the use cases.

Usenet:A worldwide network of UNIX systems, with decentralized administration,used for electronic mail and transmission by special-interest discussion groups. Itwas originally implemented using UNIX-to-UNIX copy program (UUCP) softwareand telephone connections; that method of communication remains important,althoughmore modern methods are also used.

variable:

A data item whose value may change during program execution.

visual component:

A visual component has a visual representation that requires physical space on thedisplay surface of a parent application.



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VRML:The Virtual Reality Modeling Language (VRML) is a specification for three-dimensional rendering used with Web browsers.

weaving:The act of creating and linking Web pages.

Web:See World Wide Web.

Web server:Software that uses the client/server model and the World Wide Web's HypertextTransfer Protocol (HTTP) to provide services to Web clients.

World Wide Web:A hypertext information and communication system popularly used on the Internetcomputer network with data communications operating according to a client-servermodel. Web clients (browsers) can access multiprotocol and hypermediainformation by using an addressing scheme.

WWW:See World Wide Web.


Documents

Java Glossary