Glossary of Terms

A

Abstract Class

    Generally speaking well designed class hierarchies contain concepts
    that are more general or abstract as one moves closer to the base or
    root of the hierarchy, and more specialized or detailed as one moves
    down the hierarchy. Near the root of the hierarchy the ideas that a
    class represents may be so general that they are more like a
    framework for other classes than specific instances of something
    you use.

    Experience in OOD indicates that the identification of these
    frameworks facilitates the design of class hierarchies that
    have a clear structure (i.e., work really well).

    An abstract class is a mechanism for grouping together collections
    or groups of items having similar properties or functions. Abstract
    classes must contain at least one abstract method. An abstract method
    is a placeholder for methods that are guarenteed to be implemented
    by all of the nonabstract subclasses. An abstract class cannot be
    instantiated -- only the subclasses can be instantiated.

Abstract Window Toolkit (AWT)

    The Java API that gives programmers access to Java graphics
    functionality, such as buttons, scroll bars, windows, and so forth.

Applet

    A Java mini-program that runs within a browser or viewer, usually
    as part of a html page.

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J

Java Application

    A standalone Java program, usually executed by giving the
    command line sequence

      prompt >> java myApplication.class

    or more simply

      prompt >> java myApplication

Java Development Kit (JDK)

    A set of tools, examples, help files and source and class code for a
    given platform that provides an API so programmers can write java
    applications and applets.

K

Kernel

    The term kernel describes the set of programs in an operating system
    that implements the most primitive of that system's functions. While
    the precise interpretation of "kernel" is system dependent, generally
    speaking, four types of functions are covered: 

    (1) Process management. Routines for switching processes among 
        processors, scheduling processes, sending messages, and so forth.

    (2) Memory management. Routines for fetching pages to/from main
        memory.

    (3) Basic I/O control. Routines for starting I/O requests on particular
        channels or devices, allocating and releasing I/O buffers.

    (4) Security. Routines for enforcing the access and information-flow
        control policies of the system.

    Some kernels also contain routines for handling interrupts.

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