Introduction to Java as a Programming Platform

The first release of Java in 1996 generated an incredible amount of excitement, not just in the computer press, but in mainstream media such as the New York Times, the Washington Post, and BusinessWeek. Java has the distinction of being the first and only programming language that had a ten-minute story on National Public Radio. [ [ ...]

Java Applets and the Internet

The idea here is simple: Users will download Java bytecodes from the Internet and run them on their own machines. Java programs that work on web pages are called applets. To use an applet, you only need a Java-enabled web browser, which will execute the bytecodes for you. You need not install any software. You [ [ ...]

A Short History of Java

This section gives a short history of Java’s evolution. It is based on various published sources (most importantly an interview with Java’s creators in the July 1995 issue of SunWorld’s online magazine). Java goes back to 1991, when a group of Sun engineers, led by Patrick Naughton and James Gosling (a Sun Fellow and an [ [ ...]

Common Misconceptions about Java

This chapter closes with a commented list of some common misconceptions about Java. Java is an extension of HTML. Java is a programming language; HTML is a way to describe the structure of a web page. They have nothing in common except that there are HTML extensions for placing Java applets on a web page. [ [ ...]

Installing the Java Development Kit (JDK)

The most complete and up-to-date versions of the Java Development Kit (JDK) are available from Oracle for Linux, Mac OS, Solaris, and Windows. Versions in various states of development exist for many other platforms, but those versions are licensed and distributed by the vendors of those platforms. 1. Downloading the JDK To download the Java [ [ ...]

Using the Command-Line Tools in Java

If your programming experience comes from a development environment such as Microsoft Visual Studio, you are accustomed to a system with a built-in text editor, menus to compile and launch a program, and a debugger. The JDK contains nothing even remotely similar. You do everything by typing in commands in a terminal window. This sounds [ [ ...]

Using an Integrated Development Environment in Java

In the preceding section, you saw how to compile and run a Java program from the command line. That is a useful skill for troubleshooting, but for most day-to-day work, you should use an integrated development environment. These environments are so powerful and convenient that it simply doesn’t make much sense to labor on without [ [ ...]

JShell – Java Shell tool

In the preceding section, you saw how to compile and run a Java program. Java 9 introduces another way of working with Java. The JShell program provides a “read-evaluate-print loop,” or REPL. You type a Java expression; JShell evaluates your input, prints the result, and waits for your next input. To start JShell, simply type [ [ ...]

A Simple Java Program

Let’s look more closely at one of the simplest Java programs you can have—one that merely prints a message to console: public class FirstSample { public static void main(String[] args) { System.out.println(“We will not use ‘Hello, World!'”); } } It is worth spending all the time you need to become comfortable with the framework of [ [ ...]

Comments in Java

Comments in Java, as in most programming languages, do not show up in the executable program. Thus, you can add as many comments as needed without fear of bloating the code. Java has three ways of marking comments. The most common form is a //. Use this for a comment that runs from the // [ [ ...]

Data Types in Java

Java is a strongly typed language. This means that every variable must have a declared type. There are eight primitive types in Java. Four of them are integer types; two are floating-point number types; one is the character type char, used for code units in the Unicode encoding scheme (see Section 3.3.3, “The char Type,” [ [ ...]

Variables and Constants in Java

As in every programming language, variables are used to store values. Con­stants are variables whose values don’t change. In the following sections, you will learn how to declare variables and constants. 1. Declaring Variables In Java, every variable has a type. You declare a variable by placing the type first, followed by the name of [ [ ...]

Operators in Java

Operators are used to combine values. As you will see in the following sec­tions, Java has a rich set of arithmetic and logical operators and mathematical functions. 1. Arithmetic Operators The usual arithmetic operators +, -, *, / are used in Java for addition, subtrac­tion, multiplication, and division. The / operator denotes integer division if [ [ ...]

Strings in Java

Conceptually, Java strings are sequences of Unicode characters. For example, the string “Java\u2122” consists of the five Unicode characters J, a, v, a, and ™. Java does not have a built-in string type. Instead, the standard Java library contains a predefined class called, naturally enough, String. Each quoted string is an instance of the String [ [ ...]

Java Input and Output

To make our example programs more interesting, we want to accept input and properly format the program output. Of course, modern programs use a GUI for collecting user input. However, programming such an interface requires more tools and techniques than we have at our disposal at this time. Our first order of business is to [ [ ...]

Control Flow in Java

Java, like any programming language, supports both conditional statements and loops to determine control flow. We will start with the conditional statements, then move on to loops, to end with the somewhat cumbersome switch statement that you can use to test for many values of a single expression. 1. Block Scope Before learning about control [ [ ...]

Big Numbers in Java

If the precision of the basic integer and floating-point types is not sufficient, you can turn to a couple of handy classes in the java.math package: BigInteger and BigDecimat. These are classes for manipulating numbers with an arbitrarily long sequence of digits. The BigInteger class implements arbitrary-precision integer arithmetic, and BigDecimat does the same for [ [ ...]

Arrays in Java

Arrays hold sequences of values of the same type. In the following sections, you will see how to work with arrays in Java. 1. Declaring Arrays An array is a data structure that stores a collection of values of the same type. You access each individual value through an integer index. For example, if a [ [ ...]

Introduction to Object-Oriented Programming

Object-oriented programming, or OOP for short, is the dominant programming paradigm these days, having replaced the “structured” or procedural program­ming techniques that were developed in the 1970s. Since Java is object- oriented, you have to be familiar with OOP to become productive with Java. An object-oriented program is made of objects. Each object has a [ [ ...]

Using Predefined Classes in Java

You can’t do anything in Java without classes, and you have already seen several classes at work. However, not all of these show off the typical features of object orientation. Take, for example, the Math class. You have seen that you can use methods of the Math class, such as Math.random, without needing to know [ [ ...]