by John December and David Gulbransen
API (Application Programming Interface) A set of packages containing various classes and methods that Java programmers use to create programs.
ASCII American Standard Code for Information Interchange. A 7-bit character code that can represent 128 characters, some of which are control characters used for communications control that are not printable.
applet A Java program that can be included in an HTML page with the <APPLET> HTML tag and viewed with a Java-enabled browser.
Applet Package A collection of methods and classes provided with the Java Developer’s Kit designed for use in creating applets with Java.
appletviewer The program included in the Java Developer’s Kit to view applets without a full WWW browser.
application A standalone program that executes independently of a Java-enabled browser. You can create an application by using the java Java interpreter, which is included in the Java Developer’s Kit.
attribute A property of an HTML element, specified in the starting tag of the element. The attribute list of the <APPLET> tag is used to identify the location of applet source code (with the codebase attribute) and the name of the
Java class (with the code attribute).
AWT (Abstract Window Toolkit) A package from the Java API that enables applets and applications to use graphical user interface components such as windows, buttons, and scrollbars.
block The code between matching curly braces, { and }.
boolean A data type that can store the value true or false.
browser A software program for accessing the World Wide Web; a synonym for a Web client.
bytecode The machine-readable code created as the result of compiling a Java language source file; this is the code distributed across the network to run an applet. Bytecodes are architecture-neutral; the Java-capable browser ported to a
particular platform interprets them.
child A subclass of a class (its parent class); it inherits public (and protected) data and methods from the parent class.
class A template for creating objects. A class defines data and methods; a class is a unit of organization in a Java program. A class can pass on its public data and methods to its subclasses.
compiler A software program that translates human-readable source code into machine-readable code.
component An object type in the AWT for visible user interface elements (such as a button, list box, or scrollbar).
constructor A method named after its class. A constructor method is invoked when an object of that class is created.
content handler A program loaded into the user's HotJava browser that interprets files of a type defined by the Java programmer. The Java programmer provides the necessary code for the user's HotJava browser to display and interpret this
special format.
CGI (Common Gateway Interface) A standard for programs to interface with Web servers.
client A software program that requests information or services from another software application (server) and displays this information in a form required by its hardware platform.
domain name The alphabetic name for a computer host; this name is mapped to the computer's numeric Internet Protocol (IP) address.
firewall A method for providing Internet security in which computers located on a common Local Area Network all use one machine (or firewall) as a gateway to the Internet. Firewalls restrict the type of traffic flowing in and out
from the local network to the Internet.
FTP (File Transfer Protocol) A means to exchange files across a network.
garbage collection The process by which memory allocated for objects in a program is reclaimed. Java automatically performs this process.
.GIF (Graphic Interchange Format) A type of graphic file format developed by CompuServe. GIF files use a data compression technique to create smaller graphic files with little loss in image quality.
HTML (Hypertext Markup Language) The mechanism used to create Web pages; Web browsers display these pages according to a browser-defined rendering scheme.
HTTP (Hypertext Transfer Protocol) The native protocol of the Web, used to transfer hypertext documents.
HotJava A Web browser designed to execute applets written in the Java programming language.
hypertext Text that is not constrained to a single linear sequence. Hypertext documents contain special embedded “links” which allow users to connect to other documents on a similar topic.
imagemap A graphic inline image on an HTML page that potentially connects each pixel or region of an image to a Web resource; users retrieve the resources by clicking the image.
infinite loop See infinite loop.
inheritance The ability to define a child class that has all of the functionality of its parent class.
instance An object.
interface A set of methods that Java classes can implement.
Internet The cooperatively run, globally distributed collection of computer networks that exchange information through the TCP/IP protocol suite.
Java An object-oriented programming language for creating distributed, executable applications.
javac The Java compiler provided with the Java Developer’s Kit.
Java-enabled browser A World Wide Web browser that can display Java applets.
JDK (Java Developer’s Kit) A collection of tools, documentation, and examples designed to provide Java programmers with the resources needed to complete applets and applications. It includes the java compiler, the java
debugger, and the appletviewer.
Java Virtual Machine The software ‘‘machine’’ which actually executes all Java programs. The Java Virtual Machine is built into the appletviewer, and any Java capable web browsers.
method A function that can perform operations on data.
MIME (Multipurpose Internet Mail Extensions) A specification for multimedia document formats.
native methods Class methods that are declared in a Java class but implemented in C.
Net, the A slang term for the Internet. (Also a bad movie starring Sandra Bullock.)
OOP (object-oriented programming) A new programming paradigm based on the idea that programs can be broken down into component parts.
object An instance of a class.
overload To use the same name for several items in the same scope; Java methods can be overloaded.
package A set of classes with a common high-level function declared with the package keyword.
parameter (HTML) A name and value pair identified by the Name and Value attributes of the <PARAM> tag used inside an <APPLET> tag.
parent class The originating class of a given subclass.
protocol handler A program that is loaded into the user's HotJava browser and that interprets a protocol. These protocols include standard protocols, such as HTTP, and programmer-defined protocols.
proxy An intermediary between a client software (such as a browser) and server software (such as a web site). Proxy servers provide an added level of security.
scope The program segment in which a reference to a variable is valid.
server A software application that provides information or services based on requests from client programs.
server-push animation An animation technique in which a series of images are ““pushed”” to the web browser by the web server. Server-push animation is dependent on network speed, and is a significant performance
hit on the web server.
site File section of a computer on which Web documents (or other documents served in another protocol) reside, for example, a Web site, a Gopher site, or an FTP site.
Solaris Sun Microsystems' software platform for networked applications. Solaris includes an operating system, SunOS.
SPARC (Scalable Processor ARChitecture) Based on a a reduced instruction set computer (RISC) concept in which a microprocessor is designed for very efficient handling of a small set of instructions. (See http://www.sparc.com/.)
subclass See child.
tag The code used to make up part of an HTML element; for example, the TITLE element has a starting tag, <TITLE>, and an ending tag, </TITLE>.
TCP/IP (Transmission Control Protocol/Internet Protocol) The set of protocols used for network communication on the Internet.
thread A sub-set of code in a Java application that actually runs in conjunction with the rest of the program. Threads can be thought of as a program within a program and are often necessary to deal with complex user interfaces.
Unicode A character set that supports many world languages.
URL (Uniform Resource Locator) The scheme for addressing on the Web; a URL identifies a resource on the Web.
Usenet A system for disseminating asynchronous text discussion among cooperating computer hosts; The Usenet discussion space is divided into newsgroups, each on a particular topic or subtopic.
Web See WWW.
WWW (World Wide Web) A hypertext information and communication system popularly used on the Internet computer network with data communications operating according to a client/server model. Web clients (browsers) can access multiprotocol
and hypermedia information using an addressing scheme.
Web server Software that provides the services to Web clients.