A.P. Computer Science

Adapter Class

A Java class that allows another class to implement an interface class without implementing all of its methods.

Container

A Java class that allows the programmer to froup window objects for placement in a window.

Border Layout

A Java layout class that allows the programmer to place window objects in five areas (north,south,east,west, and center) pf a window. Border layout is the default layout for Java applications

Abstract Windowing Toolkit (AWT)

A Java package that contains the definitions of classes used to set up graphical user interfaces.

Applet

A Java program that can be downloaded and run on a Web browser.

Bit

A binary digit.

Buffer

A block of memory into which data are placed for transmission to a program, usually with file or string processing.

Abstract Data Type (ADT)

A class of objects, a defined set of properties of those objects, and a set of operations for processing the objects.

Concrete Class

A class that can be instantiated. See also abstract class.

Abstract Class

A class that defines attributes and methods for subclasses but is never instantiated.

Contained Class

A class that is used to define a data object within another class.

Array List

A class that represents a linear sequence of zero or more elements and supports many types of operations, including constant-time access by index position.

Aggregation

A common relationship between two classes in which an object of one class contains an object of the other class. Also called the has-a relationship.

Application

A complete program

Client

A computational object that recieves a service from another computational object.

Assembly Language

A computer language that allows the programmer to express operations and memory addresses with mnemonic symbols.

Compiler

A computer program that automaticallu converts instructions in a high level language to machine language.

Cancallation Error

A condition in which data are lost because of differences in the precision of operands.

Class Constant

A constant that is visible to all instances of a class and, if public, is access by specifying the class name.

Bitmap

A data structure used to represent the values and positions of points on a computer screen or image.

Array

A data structure whose elements are accessed by means of an array.

Class

A description of the attributes and behavior of a set of computational objects.

Binary Digit

A digit, either 0 or 1, in the binary number system. Program instructions are stored in memory using a sequence of binary digits. See also bit.

Complete Code Coverage

A set of tests in which every line in a program is executed at least once.

Alias

A situation in which two or more names in a program can refer to the same memory location. An alias can cause subtle side effects.

Arithmetic Overflow

A situation that arises when the computer's memory cannot represent the number resulting from an arithmetic operation.

Collection

A software object that can contain zero or more other objects and that allows programmers to access, insert, or remove these objects.

Client Handler

A software object, typically running as an independent thread dedicated to one client, which serves the requests of that client.

Bubble Sort

A sorting algorithm that swaps consecutive elements that are out of order to bubble the elements to the top or bottom on each pass.

Control Statement

A statement that controls the flow of execution of program statements.

Comound Statement

A statement that uses the symbols [ and ] to group several statements and data declarations as a unit. See also block.

Absolute Path Name

A string that specifies the location of a resource, such as an HTML file, on a Web server.

Control Structure

A structure that controls the flow of execution of program statements.

Constant

A symbol whose value cannnot be changed.

Boundary Condition

A value at which two equivalence classes meet.

Argument

A value or expression passed in a method call.

Actual Parameter

A variable or expression contained in a method call and passed to that method. (See also formal parameter)

Class (static) variable

A variable that is visible to all instances of a class and, if public, is accessed by specifying the class name.

Accumulator

A variable used for the purpose of summing successive values of some other variable.

Counter

A variable used to count the number of times some process is completed.

Button Object

A window object that allows the user to select an action by clicking a mouse.

Activation Record

An area of computer memory that keeps track of a method call's parameters, local values, return value, and the caller's return address. (See also runtime stack)

Block

An area of program text, enclosed in Java by the symbols { }, that contains statements and data declarations.

Compound Assignment

An assignment operation that performs a designated operation, suvh as additionm before storing the result in a variable.

Compilation Error

An error detected when the program is being compiled. See also design error, runtime error, and syntax error.

Boolean Expression

An expression whose value is either true or false. See also compound Boolean expression and simple Boolean expression.

Address

An integer value that the computer can use to reference a location. Often called address of a memory location.

Component

An object that supports the display of an image, such as a button, menu item, or window, in a graphical user interface.

Concatenation

An operation in which the contents of one data structure are placed after the contents of another data structure.

Cast

An operator that is used to convert a value of one type to a value of a different type.

Call

Any reference to a method by an executable statement. Also reffered to as invoke.

Compatible Type

Expressions that have the same base type. A formal parameter and an actual parameter must be of compatible type, and the operands of an assignment statement must be of compatible type.

Compound Boolean Expression

Refers to the complete expression when logical connectives and negation are used to generate Boolean values. See also Boolean expression and simple Boolean expression.

Conditional Statement

See selection statement.

Abstract

Simplified or partial, hiding detail.

Abstraction

Simplified view of a task or data structure that ignores complex detail.

Assertion

Special comments used with if statements and loops that state what you expect to happen and when certain conditions will hold.

Control Unit

The part of the central processing unit that controls the operation of the rest of the computer.

Arithmetic/Logic Unit (ALU)

The part of the central processing unit that performs arithmetic operations and evaluates expressions.

Analysis

The phase of the software life cycle in which the programmer describes what the program will do.

Complexity Analysis

The process of deriving a formula that expresses the rate of growth or work or memory as a function of the size of the data or the problem that it solves.

Binary Search

The process of examining a middle value of a sorted array to see which half contains the value in question and halving until the value is located.

Context Switch

The process of saving and restoring information required to allow one thread to relinquish the CPU and another thread to acquire it.

Coding

The process of writing executable statements that are part of a program to solve a problem.

Boxing

The process whereby the Java Virtual Machine automatically wraps values or primative types in objects so they can be stored in collections.

Aspect Ratio

The ratio of the width of an image or viewing area to its height.

Array Index

The relative position of the components of an array.

Behavior

The set of actions that a class of objects supports.

Assignment Operator

The symbol =, which is used to store a value in a variable.

Call Stack

The trace of method calls that appears when Java throws an exception during program execution.

Controller

A set of software components that detects and handles user interactions with a software system.

Algorithm

A finite sequence of effective statements that, when applied to a problem, will solve it.

Big-O-Notation

A formal notation used to express the amount of work done by an algorithm or the amount of memory used by an algorithm.

C-Curve

A fractal shape that resembles the letter C.

Class Diagram

A graphical notation that describes the relationships among the classes in a software system.

Coordinate System

A grid that allows a programmer to specify positions of points in a plane or of pixels on a computer screen.

Count Controlled Loop

A loop that stops when a counter variable reaches a specified limit.

Central Processing Unit (CPU)

A major hardware component that consists of the arithmetic/logic unit and the control unit.

Client/Server Relationship

A means of describing the organization of computing resources in which one resource provides a service to another resource.

Associative Link

A means of recognizing and accessing items in a network structure, such as the World Wide Web.

Auxillaty Storage Device

A medium external to primary memory, such as a disk or flash stick, which can store data.

Cohesive Method

A method designed to accomplish a single task.

Bottom-Up Implementation

A method of coding a program that starts with lower-level modules and a test driver module.

Assignment Statement

A method of putting values into memory locations.

Binary Search Algorithm

A method of searching a collection of items with a natural ordering that allows the search to discard one half of the elements on each pass.

Class (static) method

A method that is invoked when a message is sent to a class.

Constructor

A method that is run when an object is instantiated, usually to initalize that object's instance variables.

Abstract Method

A method that is specified but not implemented in an abstract class. The subclesses must implement this method.

Accessor

A method used to examine an attribute of an object without changing it.

Combinatorial Explosion

A multiplicative growth.

Association

A pair of items consisting of a key and a value.

Attribute

A property that a computational object models, such as the balance in a bank account.

Byte

A sequence of bits used to encode a character in memory. See also word.

Arithmetic Expression

A sequence of operands and operators that computes a value.

Application Software

Programs that allow human users to accomplish specialized taskes, such as word processing or database management.

Comments

Nonexecutable statements used to make a program more readable.

ASCII Character Set

The American Standard Code for Information Interchange ordering for a character set.

Conjunction

The connection of two Boolean expressions using the logical operator %% (AND), returning false if at least one of the expressions is false or true if they are both true.

Byte Code

The kind of object code generated by a Java compiler and interpreted by a Java virtual machine. Byte code is platform independent.

Character Set

The list of characters available for data and program statements.