glossary - it.hessercan.com · applet—a java program that is called from within another...

GlossaryAabsolute path—a complete file path thatdoes not require any other information tolocate a file on a system.

abstract class—a class from which noconcrete objects canbe instantiated, butwhichcan serve as a basis for inheritance. Abstractclasses usually have one or more emptyabstractmethods.Contrastwith concrete class.

abstract data type—a type whoseimplementation is hidden and accessedthrough its public methods.

abstract method—a method declared withthe keyword abstract; it is a method withno body that must be implemented in asubclass.

abstraction—the programming featurethat allows a method name to encapsulatemultiple statements.

accelerator—a key combination thatcauses a menu item to be chosen, whetheror not the menu item is visible.

access modifier—an access specifier.

access specifier—defines thecircumstances under which a class can beaccessed and the other classes that have theright to use a class.

accessor methods—methods that returninformation about an object.

accumulating—the process of repeatedlyincreasing a value by some amount toproduce a total.

action key—a keyboard key that does notgenerate a character.

actionPerformed(ActionEvent e)method—a method that defines the actionsthat occur in response to an event.

actual parameters—the arguments in amethod call. Contrastwith formal parameters.

acyclic gradient—a fill pattern in which acolor shift occurs once between two points.

adapter class—a class that implements allthe methods in an interface, providing anempty body for each method.

add and assign operator—an operatorthat alters the value of the operand on theleft by adding the operand on the right to it;it is composed of a plus sign and an equalsign ( += ).

add() method—a method that addscomponents to a container.

addActionListener() method—amethod that tells a class to expectActionEvents.

addPoint() method—a method thatadds points to a Polygon object.

ad-hoc polymorphism—polymorphismthat occurs when a single method name can

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be used with a variety of data types becausevarious implementations exist; it is anothername for method overloading.

aggregation—a type of composition inwhich a class contains one or moremembers of another class that wouldcontinue to exist without the object thatcontains them.

algorithm—a process or set of steps thatsolves a problem.

Allman style—the indent style in whichcurly braces are aligned and each occupiesits own line; it is named for Eric Allman, aprogrammer who popularized the style.Contrast with K & R style.

ambiguous—describes a situation in whichthe compiler cannot determine whichmethod to use.

anonymous classes—nested, local classesthat have no identifier.

anonymous object—an unnamed object.

append() method—a StringBuilderclass method that adds characters to theend of a StringBuilder object.

applet—a Java program that is called fromwithin another application, frequently aWeb page.

Applet Viewer—a program that comes withthe JDK and displays applets without usinga Web browser.

appletviewer command—a command thatstarts the Applet Viewer.

application software—programs thatperform tasks for users. Contrast withsystem software.

application-triggered painting—paintingoperations that occur when the internalstate of a component has changed. Contrastwith system-triggered painting.

arc—a portion of a circle.

architecturally neutral—describes thefeature of Java that allows a program to runon any platform.

argument index—in a printf()statement, an integer that indicates theposition of an argument in the argumentlist.

arguments—data items sent to methods ina method call.

arithmetic operators—operators used toperform calculations with values.

array—a named list of data items that allhave the same type.

ArrayList class—a Java class thatprovides a dynamically resizable containerthat stores lists of objects.

Arrays class—a built-in Java class thatcontains many useful methods formanipulating arrays, such as methods tosearch, fill, compare, and sort arrays.

ascending order—the order of objectsarranged from lowest to highest value. Seealso descending order.

ascent—one of three measures of a Font’sheight; it is the height of an uppercasecharacter from a baseline to the top of thecharacter. See also leading and descent.

ASCII—an acronym for American StandardCode for Information Interchange, acharacter set widely used to representcomputer data.

assert statement—a statement thatcreates an assertion.

assertion—a Java language feature that canhelp detect logic errors and debug aprogram.

assignment—the act of providing a valuefor a variable.

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assignment operator—the equal sign ( = );any value to the right of the equal sign isassigned to the variable on the left of theequal sign.

associativity—describes the order in whichoperands are used with operators.

at run time—describes the period of timeduring which a program executes.

attributes—the characteristics that definean object as part of a class.

Bback buffer—the offscreen image duringdouble buffering.

base class—a class that is used as a basisfor inheritance.

BasicStroke—a class that defines linetypes and implements the Stroke interface.

batch processing—processing thatinvolves performing the same tasks withmany records, one after the other.

binary files—files that contain data thathas not been encoded as text; their contentsare in binary format.

binary numbering system—a numberingsystem based on two digits, 0 and 1, inwhich each column represents a value twotimes higher than the column to its right.

binary operators—operators that requiretwo operands.

bit—a binary digit, 0 or 1, used to representcomputerized values.

black box—a device that can be used solelyin terms of input and output without regardto how it works internally.

blank final—a final variable that hasnot yet been assigned a value.

block—the code between a pair of curlybraces.

block comments—comments that startwith a forward slash and an asterisk ( /* )and end with an asterisk and a forward slash( */ ). Block comments can appear on a lineby themselves, on a line before executablecode, or on a line after executable code.Block comments also can extend across asmany lines as needed. Contrast with linecomments.

block line transfer or blitting—the act ofcopying contents from one surface toanother.

Boolean values—true or false values; everycomputer decision results in a Booleanvalue.

boolean variable—a variable of theboolean data type that can hold only one oftwo values—true or false.

BorderLayout—a layout manager thatdivides a container into five regions.

BorderLayout manager—the defaultmanager class for all content panes.

BoxLayout manager—a layout managerthat allows multiple components to be laidout either vertically or horizontally. Thecomponents do not wrap, so a verticalarrangement of components, for example,stays vertically arranged when the frame isresized.

bubble sort—a type of sort in which pairsof items are compared and, if necessary,swapped so that the smallest items “bubble”to the top of the list, eventually creating asorted list.

buffer—a memory location that holds datatemporarily—for example, during input andoutput operations.

ButtonGroup—a UI component thatgroups several components, such asJCheckBoxes, so a user can select only oneat a time.

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byte—the data type that holds very smallintegers, from –128 to 127.

bytecode—programming statements thathave been compiled into binary format.

Ccall a procedure—to invoke a method.

call stack—the memory location wherethe computer stores the list of methodlocations to which the system must return.

called method—a term used to describethe relationship between two methods; amethod that is invoked by another.

calling method—a term used to describethe relationship between two methods; amethod that invokes another.

camel casing—a naming style in which anidentifier begins with a lowercase letter andsubsequent words within the identifier arecapitalized. Contrast with Pascal casing.

capacity—an attribute of an ArrayListwhose value is the number of items it canhold without having to increase its size.Also, with a StringBuilder object, theactual length of the buffer, as opposed tothat of the string contained in the buffer.

capacity() method—a StringBuilderclass method that returns the actual length,or capacity, of the StringBuilder object.

CardLayoutmanager—a layout managerthat generates a stack of containers orcomponents, one on top of another.

cast operator—an operator that performsan explicit type conversion; it is created byplacing the desired result type inparentheses before the expression to beconverted.

catch block—a segment of code that canhandle an exception that might be thrownby the try block that precedes it.

catch or specify requirement—the Javarule that checked exceptions requirecatching or declaration.

char—the data type that holds any singlecharacter.

character—any letter, number, or specialsymbol (such as a punctuation mark) thatmakes up data.

Character class—a class whoseinstances can hold a single character value.This class also defines methods that canmanipulate or inspect single-character data.

charAt() method—a String andStringBuilder class method that requiresan integer argument that indicates theposition of the character that the methodreturns.

checked exceptions—exceptions that aprogrammer should plan for and fromwhich a program should be able to recover.Contrast with unchecked exceptions.

child class—a derived class.

class—a group or collection of objects withcommon properties.

class body—the set of data items andmethods between the curly braces thatfollow the class header.

class client—an application or class thatinstantiates objects of another class. Seealso class user.

class definition—a description of attributesand methods of objects instantiated from aclass.

class diagram—a visual tool that providesan overview of a class. It consists of arectangle divided into three sections—thetop section contains the name of the class,the middle section contains the names anddata types of the attributes, and the bottomsection contains the methods.

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class methods—static methods that donot have a this reference (because theyhave no object associated with them).

class user—an application or class thatinstantiates objects of another prewrittenclass. See also class client.

class variables—static variables that areshared by every instantiation of a class.

class-level Javadoc comments—Javadoccomments that provide a description of aclass and that should be placed above thecode that declares a class.

clean build—a compilation that is createdafter deleting all previously compiledversions of a class.

clearRect() method—a method thatdraws a rectangle using the backgroundcolor to create what appears to be an emptyor “clear” rectangle.

client method—a method that callsanother method.

close the file—to make a file no longeravailable to an application.

closer in scope—a term that describes thestatus of a local variable over others that itshadows.

collision—describes a class-namingconflict.

Color class—a class that defines built-incolors.

comes into scope—describes whathappens to a variable when it is declared.Contrast with goes out of scope.

comma-separated values (CSV)—fieldsthat are separated with a comma.

commands—program statements.

comment out—the technique of turning aprogram statement into a comment so thecompiler will not execute its command.

compareTo() method—a Stringclass method used to compare twoStrings; the method returns a number thatdescribes the differences between theStrings.

comparison operator—a relationaloperator.

compiler—a program that translateslanguage statements into machine code. Acompiler translates an entire programbefore executing it. Contrast withinterpreter.

compile-time error—an error for whichthe compiler detects a violation of languagesyntax rules and is unable to translate thesource code to machine code.

composition—describes the relationshipbetween classes when an object of one classis a data field within another class. See alsohas-a relationship.

computer file—a collection of storedinformation in a computer system.

computer program—a set of instructionsthat tells a computer what to do; software.

computer simulations—programs thatattempt to mimic real-world activities sothat their processes can be improved or sothat users can better understand how thereal-world processes operate.

concatenated—describes values that areadded onto the end of another value.

concatenation—the process of joining avariable to a string to create a longer string.

concrete class—a nonabstract class fromwhich objects can be instantiated. Contrastwith abstract class.

conditional operator—an operator thatrequires three expressions separated with aquestion mark and a colon; the operator is

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used as an abbreviated version of the if...else structure.

confirm dialog box—a window that can becreated using the showConfirmDialog()method in the JOptionPane class and thatdisplays the options Yes, No, and Cancel.

console applications—programs thatsupport character output to a computerscreen in a DOS window.

constant—describes values that cannot bechanged during the execution of anapplication.

constructor—a method that establishes anobject.

consume—to retrieve and discard an entrywithout using it.

container—a type of component that holdsother components so they can be treated asa single entity.

containment hierarchy—a tree ofcomponents that has a top-level containeras its root (that is, at its uppermost level).

content pane—a component that containsall the visible components in a top-levelcontainer’s user interface.

copyArea() method—a method thatcopies any rectangular area to a newlocation.

counter-controlled loop—a definite loop.Contrast with event-controlled loop.

counting—the process of continuallyincrementing a variable to keep track of thenumber of occurrences of some event.

crash—a premature, unexpected, andinelegant end to a program.

cyclic gradient—a fill pattern in which ashift between colors occurs repeatedlybetween two points.

Ddata fields—data variables declared in aclass outside of any method.

data files—files that consist of relatedrecords that contain facts and figures,such as employee numbers, names, andsalaries.

data type—describes the type of data thatcan be stored in a variable, how muchmemory the item occupies, and what typesof operations can be performed on the data.

dead code—unreachable statements.

debugging—the process of locating andrepairing a program’s error.

decimal numbering system—thenumbering system based on 10 digits, 0through 9, in which each column value is10 times the value of the column to itsright.

DecimalFormat class—a class thatprovides ways to easily convert numbersinto strings, allowing leading and trailingzeros, prefixes and suffixes, grouping(thousands) separators, and the decimalseparator to be used for formatting.

decision structure—a logical structurethat involves choosing between alternativecourses of action based on some valuewithin a program.

declaration—another name for a methodheader; also, the statement that assigns adata type and identifier to a variable.

decrementing—the act of subtracting 1from a variable.

default constructor—a constructor thatrequires no arguments.

default package—the unnamed packagein which a class is placed if no package isspecified.

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definite loop—a loop that executes aspecific number of times; a counted loop.Contrast with indefinite loop.

derived class—a class that inherits from abase class.

descending order—the order of objectsarranged from highest to lowest value. Seealso ascending order.

descent—one of three measures of a Font’sheight; it measures the part of charactersthat “hang below” the baseline, such as thetails on the lowercase letters g and j. Seealso ascent and leading.

destroy() method—a method invokedin an applet when the user closes thebrowser or Applet Viewer.

development environment—a set of toolsthat helps programmers by providing suchfeatures as displaying a language’s keywordsin color.

dialog box—a GUI object resembling awindow that displays messages.

direct access files—random access files.

directories—elements in a storageorganization hierarchy. See also folders.

divide and assign operator—an operatorthat alters the value of the operand on theleft by dividing the operand on the rightinto it; it is composed of a slash and anequal sign ( /= ).

documentation comments—commentsthat automatically generate well-formattedprogram documentation.

do-nothing loop—a loop that performs noactions other than looping.

double—a data type that can hold afloating-point value of up to 14 or 15significant digits of accuracy. Contrastwith float.

double buffering—the default bufferingstrategy in which JPanels are drawnoffscreen when they are updated anddisplayed only when complete.

Double class—a wrapper class thatcontains a simple double and usefulmethods to manipulate it.

double-precision floating-point number—a type of value that is stored in a double.

do...while loop—a loop that executes aloop body at least one time; it checks theloop control variable at the bottom of theloop after one repetition has occurred.

draw3DRect() method—a method thatdraws a rectangle that appears to have“shadowing” on two of its edges—the effectis that of a rectangle that is lit from theupper-left corner and slightly raised orslightly lowered.

drawArc() method—a method thatdraws an arc.

drawLine() method—a method thatdraws a straight line between two points onthe screen.

drawOval() method—a method thatdraws an oval.

drawPolygon() method—a method thatdraws complex shapes.

drawRect() method—a method thatdraws the outline of a rectangle.

drawRoundRect() method—a methodthat draws rectangles with roundedcorners.

drawString() method—a method thatdraws a String in a JFrame or othercomponent.

dual-alternative if—a decision structurethat takes one of two possible courses ofaction. Contrast with single-alternative if.

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dummy values—values the user enters thatare not “real” data but just signals to stopdata entry.

dynamic method binding—the ability ofan application to select the correct subclassmethod when the program executes. Seealso late method binding.

dynamically resizable—describes anobject whose size can change duringprogram execution.

Eechoing the input—the act of repeating theuser’s entry as output so the user canvisually confirm the entry’s accuracy.

editable—describes a component that canaccept keystrokes.

element—one variable or object in anarray.

else clause—the part of an if...elsestatement that executes when the evaluatedBoolean expression is false.

else...if clause—a format used innested if statements in which eachinstance of else and its subsequent if areplaced on the same line.

empty body—a block with no statementsin it.

empty statement—a statement thatcontains only a semicolon.

encapsulation—the act of hiding data andmethods within an object.

endcap styles—styles applied to the endsof lines that do not join with other lines;they include CAP_BUTT, CAP_ROUND, andCAP_SQUARE.

endsWith() method—a String classmethod that takes a String argument andreturns true or false if a String object

does or does not end with the specifiedargument.

enhanced for loop—a language constructthat cycles through an array withoutspecifying the starting and ending points forthe loop control variable.

enum constants—the allowed values for anenumerated data type.

enumerated data type—a programmer-created data type with a fixed set of values.

equals() method—an Object classmethod that takes a single argument, whichmust be the same type as the type of theinvoking object, and returns a Booleanvalue indicating whether two objectreferences are equal. The method isoverridden in the String class to evaluatethe contents of two String objects todetermine if they are equivalent.

equalsIgnoreCase() method—aString class method that ignores case whendetermining if two Strings are equivalent.

equivalency operator—the operatorcomposed of two equal signs that comparesvalues and returns true if they are equal.

Error class—a class that represents moreserious errors than the Exception class—those from which a program usually cannotrecover.

escape sequence—a sequence that beginswith a backslash followed by a character;the pair frequently represents a nonprintingcharacter.

event—a result when a user takes action ona component.

event-controlled loop—an indefinite loop.Contrast with counter-controlled loop.

event-driven program—a program inwhich the user might initiate any number ofevents in any order.

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event handler—a method that executesbecause it is called automatically when anappropriate event occurs.

exception—in object-orientedterminology, an unexpected or errorcondition.

Exception class—a class comprising lessserious errors than those from the Errorclass; the Exception class representsunusual conditions that arise while aprogram is running, and from which theprogram can recover.

exception handling—an object-orientedtechnique for managing errors.

exception specification—the practice ofusing the keyword throws followed by anException type in the method header. Anexception specification is required when amethod throws a checked Exception that itwill not catch but will be caught by adifferent method.

executing—the act of carrying out aprogram statement or program.

explicit conversion—the data typetransformation caused by using a castoperator.

extended—describes classes that havedescended from another class.

extends—a keyword used to achieveinheritance in Java.

Extensible Hypertext Markup Language(XHTML)—an extension of HTML.

Ffactory methods—methods that assist inobject creation.

FAQs—frequently asked questions.

fault-tolerant—describes applications thatare designed so that they continue to

operate, possibly at a reduced level, whensome part of the system fails.

field—a data variable declared in a classoutside of anymethod. In reference to storage,a group of characters that has some meaning.

file channel—an object that is an avenuefor reading and writing a file.

Files class—a class used to performoperations on files and directories, such asdeleting them, determining their attributes,and creating input and output streams.

fill patterns—patterns that describe howdrawing objects are filled in.

fill3DRect() method—a method thatcreates filled, three-dimensional rectangles.

fillArc() method—a method thatcreates a solid arc.

fillOval() method—a method thatdraws a solid, filled oval.

fillPolygon() method—a method thatdraws a solid shape.

fillRect() method—a method thatdraws a solid, or filled, rectangle.

final—the keyword that precedes namedconstants, that describes superclassmethods that cannot be overridden in asubclass, and that describes classes in whichall methods are final.

finally block—a block of code thatexecutes at the end of a try...catchsequence.

fixed method binding—the opposite ofdynamic method binding; it occurs when asubclass method is selected while theprogram compiles rather than while it isrunning. See also static method binding.

float—a data type that can hold a floating-point value of up to six or seven significantdigits of accuracy. Contrast with double.

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floating-point—describes a number thatcontains decimal positions.

floating-point division—the operation inwhich two values are divided and either orboth are floating-point values.

flowchart—a tool that helps programmersplan a program’s logic by writing the stepsin diagram form, as a series of shapesconnected by arrows.

FlowLayoutmanager—a layout managerthat arranges components in rows acrossthe width of a Container; when the currentrow is filled, additional Components areplaced in new rows. By default, thecomponents in each row are centered.

flushing—an operation to clear bytes thathave been sent to a buffer for output butthat have not yet been output to a hardwaredevice.

folders—elements in a storage organizationhierarchy. See also directories.

Font class—a Java class that holdstypeface and size information.

for loop—a loop that can be used when adefinite number of loop iterations isrequired.

foreach loop—the enhanced for loop.

formal parameters—the variables in amethod declaration that accept the valuesfrom actual parameters. Contrast withactual parameters.

format specifier—in a printf()statement, a placeholder for a numericvalue.

format string—in a printf() statement, astring of characters that includes optionaltext (that is displayed literally) and one ormore format specifiers.

fragile—describes classes that are prone toerrors.

fully qualified identifier—describes afilename that includes the entire hierarchyin which a class is stored.

fundamental classes—basic classescontained in the java.lang package thatare automatically imported into everyprogram. Contrast with optional classes.

Ggarbage value—the unknown value storedin an uninitialized variable.

generic programming—a feature oflanguages that allows methods to be usedsafely with multiple data types.

getAvailableFontFamilyNames()method—a method that returns the namesof all available fonts.

getContentPane() method—a methodthat returns a reference to a container’scontent pane.

getDefaultToolkit() method—amethod that provides information aboutthe system in use.

getFontMetrics() method—a methodthat returns a FontMetrics object thatcontains information about the leading,ascent, descent, and height of a font.

getScreenResolution() method—amethod that returns the screen resolutionon the current system.

getScreenSize() method—a methodthat returns the screen size as a Dimensionobject.

getText() method—a method thatretrieves the String of text in a Component.

glass pane—a pane that resides above thecontent pane in a container. It can containtool tips.

goes out of scope—describes whathappens to a variable at the end of the block

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in which it is declared. Contrast with comesinto scope.

gradient fill—a gradual shift from onecolor at one coordinate point to a differentcolor at a second coordinate point.

graphical user interfaces (GUIs)—environments that allow users to interactwith a program in a graphical environment.

Graphics class—an abstract class thatdescends directly from Object and holdsdata about graphics operations andmethods for drawing shapes, text, andimages.

Graphics2D class—a class that providestools for two-dimensional drawing.

GridBagLayout manager—a layoutmanager that allows the addition ofComponents to precise locations within thegrid, as well as to indicate that specificComponents should span multiple rows orcolumns within the grid.

GridLayoutmanager—a layout managerthat divides a container surface into a grid.

Hhardware—the general term for computerequipment.

has-a relationship—a relationship basedon composition.

hash code—a calculated number used toidentify an object.

header—the first line of a method; itsdeclaration.

heavyweight components—componentsthat require interaction with the localoperating system. Contrast with lightweightcomponents.

height of a font—the sum of its leading,ascent, and descent.

hexadecimal numbering system—anumbering system based on 16 digits, 0through F, in which each columnrepresents a value 16 times higher than thecolumn to its right.

high-level programming language—alanguage that uses a vocabulary ofreasonable terms, such as “read,” “write,” or“add,” instead of referencing the sequencesof on and off switches that perform thesetasks. Contrast with low-level programminglanguage.

</html>—the tag that ends every HTMLdocument.

<html>—the tag that begins every HTMLdocument.

HTML, or Hypertext Markup Language—a simple language used to create Web pagesfor the Internet.

Iidentifier—the name of a programcomponent such as a class, object, orvariable.

if clause—the part of an if...elsestatement that executes when the evaluatedBoolean expression is true.

if...else statement—the statementthat provides the mechanism to performone action when a Boolean expressionevaluates as true, and to perform adifferent action when a Boolean expressionevaluates as false.

if statement—the single-alternativedecision statement.

image—a likeness of a person or thing.

immutable—describes objects that cannotbe changed.

implementation—the actions that executewithin a method; the method body.

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implementation hiding—a principle ofobject-oriented programming thatdescribes the encapsulation of methoddetails within a class.

implicit conversion—the automatictransformation of one data type to another.Also called promotion.

import statement—a Java statement thatallows access to a built-in Java class that iscontained in a package.

inclusion polymorphism—the situation inwhich a single method implementation canbe used with a variety of related objectsbecause they are objects of subclasses of theparameter type. See also purepolymorphism.

incrementing—the act of adding 1 to avariable.

indefinite loop—a loop in which the finalnumber of iterations is unknown. Contrastwith definite loop.

indexOf() method—a String classmethod that determines whether a specificcharacter occurs within a String. If it does,the method returns the position of thecharacter; the first position of a Stringbegins with zero. The return value is –1 ifthe character does not exist in the String.

infinite loop—a loop that never ends.

information hiding—the object-orientedprogramming principle used when creatingprivate access for data fields; a class’sprivate data can be changed or manipulatedonly by a class’s own methods, and not bymethods that belong to other classes.

inheritance—a mechanism that enablesone class to inherit, or assume, both thebehavior and the attributes of another class.

init() method—the first method calledin any applet.

initialization—the act of making anassignment at the time of variabledeclaration.

inlining—an automatic process thatoptimizes performance in which calls tofinal methods are replaced with theexpanded code of their definitions at eachmethod call location.

inner block—a block contained in an outerblock. See also inside block.

inner classes—nested classes that requirean instance. See also nonstatic memberclasses.

inner loop—a loop that is containedentirely within another loop.

input dialog box—a GUI object that asks aquestion and provides a text field in whichthe user can enter a response.

insert() method—a StringBuilderclass method that adds characters at aspecific location within a StringBuilderobject.

inside block—a block contained in anoutside block. See also inner block.

instance—an existing object of a class.

instance methods—methods used withobject instantiations. See also nonstaticmethods.

instance variables—the data componentsof a class.

instanceof operator—an operator thatdetermines whether an object that is theoperand on the left is a member ordescendant of the class that is the operandon the right.

instantiate—to create an instance; to createan object.

instantiation—an object; one tangibleexample of a class.

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int—the data type used to declarevariables and constants that store integersin the range of –2,147,483,648 to+2,147,483,647.

integer—a whole number without decimalplaces.

Integer class—a wrapper class thatcontains a simple integer and usefulmethods to manipulate it.

integer division—the operation in whichone integer value is divided by another; theresult contains no fractional part.

interactive program—an application inwhich the user makes direct requests, asopposed to one in which input comes froma file.

interface—a construct similar to a class,except that all of itsmethodsmust be abstractand all of its data (if any) must be staticfinal; it declaresmethod headers but not theinstructions within those methods. Also usedto describe the part of a method that a clientsees and uses—it includes the method’sreturn type, name, and arguments.

interpreter—a program that translateslanguage statements into machine code. Aninterpreter translates and executes onestatement at a time. Contrast with compiler.

invoke—to call or execute a method.

is-a relationship—the relationshipbetween an object and the class of which itis a member.

iteration—one loop execution.

JJApplet—a Swing class that serves as thebasis for inheritance for applets.

Java—a programming language developedby Sun Microsystems as an object-orientedlanguage used both for general-purposebusiness applications and for interactive,

World Wide Web–based Internetapplications.

Java API—the application programminginterface, a collection of information abouthow to use every prewritten Java class.

Java applications—stand-alone Javaprograms.

Java ARchive (JAR) file—a file thatcompresses the stored data.

Java Enterprise Edition (EE)—a Javaedition that includes all of the classes in theJava SE, plus a number of classes that aremore useful to programs running onservers.

Java Foundation Classes (JFC)—selectedclasses from the java.awt package,including Swing component classes.

Java interpreter—the program thatchecks bytecode and communicates withthe operating system, executing thebytecode instructions line by line within theJava virtual machine.

Java Micro Edition (ME)—a Java platformthat is used for small devices such as PDAs,cell phones, and other consumerappliances.

Java SE 7—the most recent version of Java.The full, official name is Java Platform,Standard Edition 7.

Java Virtual Machine (JVM)—ahypothetical (software-based) computer onwhich Java runs.

java.lang—the package that is implicitlyimported into every Java program and thatcontains the fundamental classes.

Javadoc—a documentation generator thatcreates Application Programming Interface(API) documentation in Hypertext MarkupLanguage (HTML) format from Java sourcecode.

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Javadoc comment—a special form ofblock comment that provides a standardway to document Java code.

Javadoc tag—a keyword within acomment that the Javadoc tool can process.

JButton—a Component the user can clickwith a mouse to make a selection.

JCheckBox—a UI component that consistsof a label positioned beside a square; a usercan click the square to display or remove acheck mark. Usually, a JCheckBox is used toturn an option on or off.

JComboBox—a UI component thatcombines two features: a display areashowing an option and a list box containingadditional options. The display area containseither a button that a user can click or aneditable field into which the user can type.

JDK—the Java Standard EditionDevelopment Kit.

JFrame—a container with a title bar andborder.

jGRASP—a development environment andsource code editor.

JLabel—a built-in Java Swing class thatholds displayable text.

JOptionPane—a Java class that producesdialog boxes.

JPanel—a plain, borderless surface thatcan hold lightweight UI components.

JScrollPane—a pane that provides scrollbars along the side or bottom, or both, sothat the user can scroll initially invisibleparts of the pane into view.

JTextField—a component into which auser can type a single line of text data.

juncture styles—styles applied to lines thatjoin; they include JOIN_MITER, JOIN_ROUND,and JOIN_BEVEL.

KK & R style—the indent style in which theopening brace follows the header line; it isnamed for Kernighan and Ritchie, whowrote the first book on the C programminglanguage. Contrast with Allman style.

key field—the field in a record that makesthe record unique from all others.

keyboard buffer—a small area of memorywhere keystrokes are stored before they areretrieved into a program. Also called thetype-ahead buffer.

KeyListener interface—an interfacethat provides methods that respond toactions the user initiates from the keyboard.The KeyListener interface contains threemethods—keyPressed(), keyTyped(), andkeyReleased().

keywords—the words that are part of aprogramming language.

Llate method binding—the ability of anapplication to select the correct subclassmethod when the program executes. Seealso dynamic method binding.

layout manager—a class that controlscomponent positioning in a UIenvironment.

leading—one of three measures of aFont’s height; it is the amount of spacebetween baselines. See also ascent anddescent.

leaf menu item—a menu item that doesnot bring up another menu.

length field—a field that contains thenumber of elements in an array.

length() method—a String classmethod that returns the length of a String.

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lexicographical comparison—acomparison based on the integer Unicodevalues of characters.

library of classes—a folder that provides aconvenient grouping for classes. See alsopackage.

lightweight components—componentswritten completely in Java that do not haveto rely on the code written to run in thelocal operating system. Contrast withheavyweight components.

line comments—comments that start withtwo forward slashes ( // ) and continue tothe end of the current line. Line commentscan appear on a line by themselves or at theend of a line following executable code.Contrast with block comments.

listener—an object that is interested in andreacts to an event.

literal constant—a value that is takenliterally at each use. See also unnamedconstant.

literal string—a series of characters thatappear exactly as entered. Any literal string inJava appears between double quotationmarks.

local classes—nested classes that are localto a block of code.

local variable—a variable known onlywithin the boundaries of a method.

logic—describes the order of programstatements that produce correct results.

logic error—an error that occurs when aprogram compiles successfully butproduces an error during execution.

logical AND operator—an operator usedbetween Boolean expressions to determinewhether both are true. The AND operatoris written as two ampersands ( && ).

logical OR operator—an operator usedbetween Boolean expressions to determine

whether either expression is true. The ORoperator is written as two pipes ( || ).

long—the data type that holds very largeintegers, from –9,223,372,036,854,775,808to 9,223,372,036,854,775,807.

look and feel—describes the defaultappearance and behavior of any userinterface.

loop—a structure that allows repeatedexecution of a block of statements.

loop body—the block of statements thatexecutes when the Boolean expression thatcontrols the loop is true.

loop control variable—a variable whosevalue determines whether loop executioncontinues.

loop fusion—the technique of combiningtwo loops into one.

lossless data compression—a set of rulesthat allows an exact replica of data to bereconstructed from a compressed version.

low-level programming language—alanguage that corresponds closely to acomputer processor’s circuitry. Contrastwith high-level programming language.Compare with machine language.

lvalue—an expression that can appear onthe left side of an assignment statement.Contrast with rvalue.

Mmachine code—machine language.

machine language—circuitry-levellanguage; a series of on and off switches.Compare with low-level programminglanguage.

magic number—a value that does not haveimmediate, intuitive meaning or a numberthat cannot be explained without additional

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knowledge. Unnamed constants are magicnumbers.

matrix—a two-dimensional array.

member-level Javadoc comments—Javadoc comments that describe the fields,methods, and constructors of a class.

menu bar—a horizontal strip that is placedat the top of a container and that containsuser options.

menus—lists of user options.

method—a program module that containsa series of statements that carry out a task.

method body—the set of statementsbetween curly braces that follow themethod header and carry out the method’sactions.

method header—the declaration or firstline of a method that contains informationabout how other methods interact with it.

method’s type—the method’s return type.

mission critical—describes any processthat is crucial to an organization.

mnemonic—a key that causes an alreadyvisible menu item to be chosen.

modulus operator—the percent sign;when it is used with two integers, the resultis an integer with the value of the remainderafter division takes place. Also called theremainder operator; sometimes called justmod.

MouseEvent—the type of event generatedby mouse manipulation.

MouseInputListener interface—aninterface that implements all the methodsin both the MouseListener andMouseMotionListener interfaces.

MouseListener interface—an interfacethat provides methods namedmousePressed(), mouseClicked(), and

mouseReleased() that are analogous to thekeyboard event methods keyPressed(),keyTyped(), and keyReleased().

MouseMotionListener interface—aninterface that provides methods namedmouseDragged() and mouseMoved() thatdetect the mouse being rolled or draggedacross a component surface.

multidimensional arrays—arrays thatcontain two or more dimensions.

multimedia—describes the use of sound,images, graphics, and video in computerprograms.

multiple inheritance—the capability toinherit from more than one class; Java doesnot support multiple inheritance.

multiply and assign operator—anoperator that alters the value of the operandon the left by multiplying the operand onthe right by it; it is composed of an asteriskand an equal sign.

mutator methods—methods that set fieldvalues.

Nnamed constant—a named memorylocation whose value cannot change duringprogram execution; in Java, its declarationincludes the keyword final.

NaN—a three-letter abbreviation for “Not anumber.”

nested—describes the relationship ofstatements, blocks, or classes when onecontains the other.

nested classes—classes contained in otherclasses.

nested if statements—describes ifstatements when one is contained withinthe other.

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new operator—an operator that allocatesthe memory needed to hold an object.

nonstatic member classes—nestedclasses that require an instance. See alsoinner classes.

nonstatic methods—methods used withobject instantiations. See also instancemethods.

nonvolatile storage—storage that does notrequire power to retain information.Contrast with volatile storage.

NOT operator—the exclamation point ( ! );it negates the result of anyBoolean expression.

null String—an empty String created bytyping a set of quotes with nothing betweenthem.

numeric constant—a number whose valueis taken literally at each use.

Oobject—an instance of a class.

Object class—a class defined in thejava.lang package that is importedautomati-cally into every Java program andthat is the base class for all other Javaclasses.

object-oriented programming—a style ofprogramming that involves creating classes,creating objects from those classes, andcreating applications that use those objects.Contrast with procedural programming.

octothorpe—the pound sign.

one-dimensional array—an array thatcontains one column of values and whoseelements are accessed using a singlesubscript. See also single-dimensional array.

open a file—the action that creates anobject and associates a stream of byteswith it.

operand—a value used in an arithmeticstatement.

operator precedence—the rules for theorder in which parts of a mathematicalexpression are evaluated.

optional classes—classes that reside inpackages that must be explicitly importedinto programs. Contrast with fundamentalclasses.

out of bounds—describes a subscript thatis not within the allowed range for an array.

outer block—a block that contains a nestedblock. See also outside block.

outer loop—a loop that contains anotherloop.

outside block—a block that contains anested block. See also outer block.

overloading—describes using one term toindicate diverse meanings, or writingmultiple methods with the same name butwith different arguments.

override a method—the action in which achild class method takes precedence overone in the parent class that has the samename and argument list.

overrides—describes what a variable ormethod does to another with the samename when it takes precedence over theother variable.

Ppackage—a named collection or library ofclasses. See also library of classes.

paint() method—a method that runswhen Java displays a screen and that iscommonly overridden in programs that usegraphics.

painting—the act of displaying orredisplaying a surface.

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parallel array—an array with the samenumber of elements as another, and forwhich the values in corresponding elementsare related.

parameters—data items received by amethod.

parent class—a base class.

parse—to break into component parts; theprocess the compiler uses to divide sourcecode into meaningful portions for analysis.

parseDouble() method—a Double classmethod that takes a String argument andreturns its double value.

parseInt() method—an Integer classmethod that takes a String argument andreturns its integer value.

parsing—the process the compiler uses todivide source code into meaningful portionsfor analysis.

Pascal casing—the style of using anuppercase letter to begin an identifier andto start each new word in an identifier.Contrast with camel casing. Compare toupper camel casing.

passed by reference—describes a variablepassed to a method when the address ispassed to the method. Contrast with passedby value.

passed by value—describes a variablepassed to a method when a copy is made inthe receiving method. Contrast with passedby reference.

passing arguments—the act of sendingarguments to a method.

path—the complete list of the disk driveplus the hierarchy of directories in which afile resides.

Path class—a Java class used to work withfile information, such as location, size,creation date, and whether the file exists.

path delimiter—the character used toseparate path components.

pattern String—an argument passed tothe DecimalFormat constructor that iscomposed of symbols that determine whata formatted number looks like.

permanent storage devices—hardwarestorage devices that retain data even whenpower is lost.

pixels—the picture elements, or tiny dotsof light, that make up the image on a videomonitor.

point size argument—an argument to theFont constructor that is an integer thatrepresents about 1/72 of an inch.

polymorphism—the feature of languagesthat allows the same word to be interpretedcorrectly in different situations based on thecontext; the act of using the same methodname to indicate different implementations.

populating an array—the act of providingvalues for all of the elements in an array.

postfix ++ or the postfix incrementoperator—an operator that is composed byplacing two plus signs to the right of avariable; it evaluates the variable, then adds1 to it. Contrast with prefix ++.

posttest loop—a loop in which the loopcontrol variable is tested after the loop bodyexecutes. Contrast with pretest loop.

preferred size—a Component’s default size.

prefix ++ or the prefix incrementoperator—an operator that is composed byplacing two plus signs to the left of avariable; it adds 1 to the variable, thenevaluates it. Contrast with postfix ++.

prefix and postfix decrement operators—operators that subtract 1 from a variablebefore and after evaluating it, respectively.

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G L O S S A R Y


pretest loop—a loop in which the loopcontrol variable is tested before the loopbody executes. Contrast with posttest loop.

primary key—a unique identifier for datawithin a database.

primary surface—the visible screensurface during double buffering.

priming read or priming input—the firstinput statement prior to a loop that willexecute subsequent input statements forthe same variable.

primitive type—a simple data type. Java’sprimitive types are byte, short, int, long,float, double, char, and boolean.

private access—refers to a field that noother classes can access.

procedural programming—a style ofprogramming in which sets of operationsare executed one after another in sequence.Contrast with object-oriented programming.

procedures—sets of operations performedby a computer program.

program—a set of written computerinstructions.

program comments—nonexecutingstatements added to a Java file for thepurpose of documentation.

program files—files that store softwareinstructions.

program statements—similar to Englishsentences; they carry out the tasks thatprograms perform.

programmer-defined data type—a typethat is created by a programmer and notbuilt into the language; a class.

promotion—an implicit conversion.

prompt—a message that requests anddescribes user input.

property—an instance variable, field, orattribute of a class.

protected—a Java keyword that providesan intermediate level of security betweenpublic and private access. Protectedmembers are those that can be used by aclass and its descendants.

pseudocode—a tool that helpsprogrammers plan a program’s logic bywriting plain English statements.

pseudorandom—describes numbers thatappear to be random but are the same set ofnumbers whenever the seed is the same.

pure polymorphism—the situation inwhich a single method implementation canbe used with a variety of related objectsbecause they are objects of subclasses of theparameter type. See also inclusionpolymorphism.

Rragged array—a two-dimensional arraythat has rows of different lengths.

random access files—files in whichrecords can be located in any order.

random access memory (RAM)—temporary, volatile storage.

random number—a number whose valuecannot be predicted.

range check—a series of statements thatdetermine within which of a set of ranges avalue falls.

range match—the process of comparing avalue to the endpoints of numerical rangesto find a category in which the valuebelongs.

real-time—describes applications thatrequire a record to be accessed immediatelywhile a client is waiting.

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record—a collection of fields that containsdata about an entity.

redeclare a variable—to attempt todeclare a variable twice—an illegal action.

reference—a variable that holds a memoryaddress.

reference to an object—the name for amemory address where the object is held.

reference types—objects that holdmemory addresses.

regionMatches() method—a Stringclass method that compares two Stringregions.

relational operator—an operator thatcompares two items; an expression thatcontains a relational operator has a Booleanvalue.

relative path—a path that depends onother path information to be complete.

remainder and assign operator—anoperator that alters the value of the operandon the left by assigning the remainder whenthe left operand is divided by the rightoperand; it is composed of a percent signand an equal sign ( %= ).

remainder operator—the percent sign;when it is used with two integers, the resultis an integer with the value of the remainderafter division takes place. Also called themodulus operator.

remove() method—a method thatremoves components from a container.

repaint() method—a method thatexecutes when a window needs to beupdated, such as when it contains newimages.

replace() method—a String classmethod that replaces all occurrences of aspecified character within a String.

rerender—to repaint or redisplay adrawing.

return a value—to send a data value froma called method back to the callingmethod.

return statement—a statement that endsa method and frequently sends a valuefrom a called method back to the callingmethod.

return type—the type of data that, uponcompletion of a method, is sent back to itscalling method.

robustness—describes the degree to whicha system is resilient to stress, maintainingcorrect functioning.

root directory—the main directory of astorage device, outside any folders.

runtime error—an error that occurs whena program compiles successfully but doesnot execute.

runtime exceptions—unplannedexceptions that occur during a program’sexecution. The term is also used morespecifically to describe members of theRuntimeException class.

rvalue—an expression that can appear onlyon the right side of an assignmentstatement. Contrast with lvalue.

Ssandbox—a safe area in which a programcan run without causing harm to otherareas of a system.

scalar—describes simple, primitivevariables, such as int, double, or char.

scientific notation—a display format thatmore conveniently expresses large or smallnumeric values; a multidigit number isconverted to a single-digit number andmultiplied by 10 to a power.

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G L O S S A R Y


scope—in reference to a variable, theportion of a program within which thevariable exists and can be referenced.

SDK—a software development kit, or a setof tools useful to programmers; the Java EEDevelopment Kit.

searching an array—the process ofcomparing a value to a list of values in anarray, looking for a match.

seed—a starting value.

seekable—describes a file channel in whichoperations can start at any specified position.

semantic errors—the type of errors thatoccur when a correct word is used in thewrong context in program code.

sequence structure—a logical structure inwhich one step follows anotherunconditionally.

sequential access file—a data file inwhich each record is stored in order, basedon the value in some field.

setCharAt() method—a StringBuilderclass method that changes a character at aspecified position within a StringBuilderobject.

setEditable() method—a method thatchanges the editable status of a JTextField.

setEnabled() method—a method thatmakes a component available or dimmedand unavailable.

setFont() method—a method thatchanges a JLabel’s font.

setLength() method—a StringBuilderclass method that changes the length of thecharacters in the String in aStringBuilder object.

setLocation() method—a method thatplaces a component at a specific locationwithin a JFrame’s content pane.

setStroke() method—a Java 2Dmethod that alters a stroke’s width.

setText() method—a method thatchanges the text in a Component that hasalready been created.

setToolTipText() method—a methodthat defines the text to be displayed in a tooltip.

shadowing—the action that occurs when alocal variable hides a variable with the samename that is further away in scope.

short—the data type that holds smallintegers, from –32,768 to 32,767.

short-circuit evaluation—describes thefeature of the AND and OR operators inwhich evaluation is performed only as far asnecessary to make a final decision.

showInputDialog() method—amethod that creates an input dialog box.

signature—a method’s name and thenumber, types, and order of arguments.

significant digits—refers to themathematical accuracy of a value.

single-alternative if—a decision structurethat performs an action, or not, based onone alternative. Contrast with dual-alternative if.

single-dimensional array—an array thatcontains one column of values and whoseelements are accessed using a singlesubscript. See also one-dimensional array.

single-precision floating-point number—a type of value that is stored in a float.

software—the general term for computerprograms.

sorting—the process of arranging a seriesof objects in some logical order.

source—a component on which an event isgenerated.

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source code—programming statementswritten in a high-level programminglanguage.

stack trace history list, or more simplystack trace—a list that displays all themethods that were called during programexecution.

standard arithmetic operators—operators that are used to performcommon calculations.

standard input device—normally thekeyboard.

standard output device—normally themonitor.

start() method—a method that executesafter the init() method in an applet andexecutes again every time the appletbecomes active after it has been inactive.

startsWith() method—a String classmethod that takes a String argument andreturns true or false if a String objectdoes or does not start with the specifiedargument, respectively.

state—the values of the attributes of anobject.

static—a keyword that means a methodis accessible and usable even though noobjects of the class exist.

static member class—a type of nestedclass that has access to all static methodsof its top-level class.

static method binding—the opposite ofdynamic method binding; it occurs when asubclass method is selected while theprogram compiles rather than while it isrunning. See also fixed method binding.

stop() method—a method invoked in anapplet when a user leaves a Web page(perhaps by minimizing a window ortraveling to a different Web page).

stream—a pipeline or channel throughwhich bytes flow into and out of anapplication.

String class—a class used to work withfixed-string data—that is, unchanging datacomposed of multiple characters.

String variable—a named object of theString class.

StringBuilder and StringBufferclasses—classes used to store andmanipulate changeable data composed ofmultiple characters that are used asalternatives to the String class.

stringWidth() method—aFontMetrics class method that returns theinteger width of a String.

stroke—a line-drawing feature in Java 2Dthat represents a single movement using adrawing tool similar to a pen or pencil.

strongly typed language—a language inwhich all variables must be declared beforethey can be used.

stub—a method that contains nostatements; programmers create stubs astemporary placeholders during theprogram development process.

style argument—an argument to the Fontconstructor that applies an attribute todisplayed text and is one of three values:Font.PLAIN, Font.BOLD, or Font.ITALIC.

subclass—a derived class.

subscript—an integer contained withinsquare brackets that indicates one of anarray’s variables, or elements.

substring() method—a String classmethod that extracts part of a String.

subtract and assign operator—anoperator that alters the value of the operandon the left by subtracting the operand on

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G L O S S A R Y


the right from it; it is composed of a minussign and an equal sign ( –= ).

subtype polymorphism—the ability of onemethod name to work appropriately fordifferent subclasses of a parent class.

super—a Java keyword that always refersto a class’s immediate superclass.

superclass—a base class.

Swing components—UI elements such asdialog boxes and buttons; their namesusually begin with J.

switch statement—a statement that usesup to four keywords to test a single variableagainst a series of exact integer or charactervalues. The keywords are switch, case,break, and default.

symbolic constant—a named constant.

syntactic salt—describes a languagefeature designed to make it harder to writebad code.

syntactic sugar—describes aspects of acomputer language that make it “sweeter,”or easier, for programmers to use.

syntax—the rules of a language.

syntax error—a programming error thatoccurs when a program contains typingerrors or incorrect language use. A programcontaining syntax errors will not compile.

system software—the set of programs thatmanage the computer. Contrast withapplication software.

System.out.printf() method—amethod used to format numeric values.

system-triggered painting—paintingoperations that occur when the system asksa component to render its contents.Contrast with application-triggeredpainting.

Ttable—a two-dimensional array; a matrix.

tag attributes—arguments that promoteactivity or describe the features of anHTML tag.

tags—HTML commands.

ternary operator—an operator that needsthree operands.

text files—files that contain data that canbe read in a text editor because the data hasbeen encoded using a scheme such asASCII or Unicode.

this reference—a reference to an objectthat is passed to any object’s nonstatic classmethod.

threads of execution—units of processingthat are scheduled by an operating systemand that can be used to create multiplepaths of control during program execution.

throw statement—a statement that sendsan Exception out of a block or a method soit can be handled elsewhere.

TOCTTOU bug—an error that occurs whenchanges take place from Time Of Check ToTime Of Use.

token—a unit of data; the Scanner classseparates input into tokens.

toLowerCase() method—a String classmethod that converts any String to itslowercase equivalent.

tool tips—popup windows that can help auser understand the purpose ofcomponents in an application; a tool tipappears when a user hovers a mousepointer over the component.

top-level class—the containing class innested classes.

top-level container—a container at thetop of a containment hierarchy. The Java

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top-level containers are JFrame, JDialog,and JApplet.

toString() method—an Object classmethod that converts an Object into aString that contains information about theObject. Also, a String class method thatconverts any object to a String.

toUpperCase() method—a String classmethod that converts any String to itsuppercase equivalent.

try block—a block of code that aprogrammer acknowledges might generatean exception.

two-dimensional array—an array thatcontains two or more columns of valuesand whose elements are accessed usingmultiple subscripts. Contrast with one-dimensional array.

type-ahead buffer—the keyboard buffer.

type casting—an action that forces a valueof one data type to be used as a value ofanother type.

type conversion—the process ofconverting one data type to another.

typeface argument—an argument to theFont constructor that is a Stringrepresenting a font. Common fonts havenames such as Arial, Century, Monospaced,and Times New Roman.

type-safe—describes a data type forwhich only appropriate behaviors areallowed.

type-wrapper classes—a method that canprocess primitive type values.

UUI components—user interfacecomponents, such as buttons and textfields, with which the user can interact.

unary cast operator—a more completename for the cast operator that performsexplicit conversions.

unary operator—an operator that usesonly one operand.

unchecked exceptions—exceptions thatcannot reasonably be expected to berecovered from while a program isexecuting. Contrast with checkedexceptions.

Unicode—an international system ofcharacter representation.

Unified Modeling Language (UML)—agraphical language used by programmersand analysts to describe classes and object-oriented processes.

unifying type—a single data type to whichall operands in an expression are converted.

uninitialized variable—a variable that hasbeen declared but that has not beenassigned a value.

unnamed constant—a constant value thathas no identifier associated with it. See alsoliteral constant.

unreachable statements—statements thatcannot be executed because the logical pathcan never encounter them; in somelanguages, including Java, an unreachablestatement causes a compiler error. See alsodead code.

upcast—to change an object to an object ofa class higher in its inheritance hierarchy.

upper camel casing—Pascal casing.

Vvalidating data—the process of ensuringthat a value falls within a specified range.

variable—a named memory locationwhose contents can be altered duringprogram execution.

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variable declaration—a statement thatreserves a named memory location.

viewport—the viewable area in aJScrollPane.

virtual classes—the name given to abstractclasses in some other programminglanguages, such as C++.

virtual key codes—codes that representkeyboard keys that have been pressed.

virtual method calls—method calls inwhich the method used is determined whenthe program runs, because the type of theobject used might not be known until themethod executes. In Java, all instancemethod calls are virtual calls by default.

void—a keyword that, when used in amethod header, indicates that the methoddoes not return any value when it is called.

volatile storage—memory that requirespower to retain information. Contrast withnonvolatile storage.

WWeb browser—a program that displaysHTML documents on the screen.

while loop—a construct that executes abody of statements continually as long asthe Boolean expression that controls entryinto the loop continues to be true.

whitespace—any combination ofnonprinting characters; for example,spaces, tabs, and carriage returns (blanklines).

wildcard symbol—a symbol used toindicate that it can be replaced by any set of

characters. In Java, the wildcard symbol isan asterisk; in an import statement, thewildcard symbol represents all the classes ina package.

window decorations—the icons andbuttons that are part of a window or frame.

windowed applications—programs thatcreate a graphical user interface (GUI) withelements such as menus, toolbars, anddialog boxes.

wrapped—to be encompassed in anothertype.

wrapper—a class or object that is “wrappedaround” a simpler element.

“write once, run anywhere” (WORA)—aslogan developed by Sun Microsystems todescribe the ability of one Java programversion to work correctly on multipleplatforms.

Xx-axis—an imaginary horizontal line thatindicates screen position.

x-coordinate—a position value thatincreases from left to right across a window.

XHTML—Extensible Hypertext MarkupLanguage, an extension of HTML.

Yy-axis—an imaginary vertical line thatindicates screen position.

y-coordinate—a position value thatincreases from top to bottom across awindow.

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glossary - it.hessercan.com · applet—a java program that is called from within another...

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