Java Programming - Glossary

Applet

An applet is a graphical Java program that executes within a Web page.

AppletViewer

AppletViewer is a utility included with the Java Development Kit that allows you to test applets without using a Web browser.

Application Programming Interface (API)

The Java API is a set of Java packages and classes included in the Java 2 Software Development Kit (SDK) that programmers use to create Java programs.

Array

An array is a special construct in Java that allows you to store a list of items of the same data type.

Branch statement

Java supports two different kinds of branch statements. The if-else is the most commonly used, and it is useful in situations where you need to conditionally execute one section of code or another. Java's other branch statement, the switch statement, is designed to choose between multiple branches of code.

Break statement

The break statement is used to exit out of a branch or loop.

Bytecode

Bytecode is the executable form of Java code, which is capable of being executed in the Java runtime system.

Class

A class is a template that defines the implementation of an object, effectively acting as a blueprint for the object. A class defines data and methods and is a unit of organization in a Java program.

Command-line arguments

Command-line arguments are information passed into a command-line application that somehow controls the way the application runs.

Comments

Comments are used to document code for the purposes of the programmer. Java supports three different types of comments://, /* */, and /** */.

Compound statement

A compound statement is a block of code that is surrounded by curly braces ({}). Compound statements allow you to use multiple lines of code in situations where a single statement is expected. A good example is the code executed in the branch of an if statement.

Conditional operator

The conditional operator acts like a shorthand if-else statement. It evaluates a test expression and conditionally evaluates another expression based on the test.

Data types

Data types dictate the type of information that can be stored in a variable. Java supports a wide range of simple data types such as int, long, float, boolean, and char. Composite data types in Java are implemented as objects. An example of a composite data type is String.

Expression

An expression usually involves an equal sign (=) and somehow manipulates one or more variables or values.

Graphical User Interface (GUI)

The program elements involved in communicating with the user through visual cues, typically utilizing both the keyboard and mouse.

Hypertext Markup Language (HTML)

HTML is the formatting language used to create Web pages.

Identifier

An identifier is a token that represents a unique name for a variable, method, class, package, and any other named Java construct.

Inheritance

Inheritance is the ability to derive new classes from existing classes in object-oriented programming.

Java 2 Software Development Kit (SDK)

The Java 2 SDK is a standard suite of tools, utilities, and related resources used to build Java applets and applications.

Java compiler

The Java compiler is the tool used to compile Java source code into executable Java programs.

Java interpreter

The Java interpreter is a program responsible for translating Java bytecode into native code that can execute on a given platform.

Keywords

Keywords are special identifiers set aside as Java programming constructs. Typical keywords in Java include int, class, for, while, new, private, and switch, to name a few.

Literals

Literals are constant values such as numbers and strings.

Loop

There are three types of loops used in Java: for loops, while loops, and do loops.

main() method

The main method is a method within a Java application that is called by the Java interpreter to run the application.

Message

In object-oriented programming, sending a message to an object to invoke a method is similar to calling a procedure in structured programming languages.

Method

A method is an isolated section of code in an object that performs a particular function.

Object

An object is a collection of data and the procedures (methods) that act on that data.

Object class

The Object class is the class that forms the root of the Java class hierarchy. The Object class serves as the basis for all Java classes, including the classes in the Java API.

Object-oriented programming (OOP)

Object-oriented programming is the implementation of a program or algorithm using objects.

Operator

An operator is a programming construct that performs an evaluation or computation on a data object or objects.

Overload

To overload is to use the same name for several items in the same scope.

Override

To override is to replace an inherited method with a newer version.

Parameter

A parameter is a name and value pair identified by the name and value attributes of the PARAM element used inside an APPLET element.

Separators

Separators are symbols used to inform the Java compiler of how code elements are grouped.

Standard I/O

Standard I/O is the most basic form of input and output available to a Java program. Java standard I/O is text-based, and operates under the premise that the computer has a standard input device (keyboard) and a standard output device (monitor).

String

A string is a Java object that represents textual information. Although you can think of a string in Java as a series of characters, strings are implemented in the String class.

Token

A token is the smallest code element in a program that is meaningful to the compiler.

Variables

Variables are locations in memory that are used to store information. You can think of variables as storage containers designed to hold data of a certain type.