Preface

We assume you are willing, even eager, to learn about all the advanced features that Java puts at your disposal. For example, we give you a detailed treatment of

When writing a book, errors and inaccuracies are inevitable. We’d very much like to know about them. But, of course, we’d prefer to learn about each of them only once. We have put up a list of frequently asked questions, bug fixes, and workarounds on a web page at http://horstmann.com/corejava. Strategically placed at the end of the errata page (to encourage you to read through it first) is a form you can use to report bugs and suggest improvements. Please don’t be disappointed if we don’t answer every query or don’t get back to you immediately. We do read all e-mail and appreciate your input to make future editions of this book clearer and more informative.

In Chapter 2, we tell you how to download and install the JDK and the program examples for this book. Then we guide you through compiling and running three typical Java programs—a console application, a graphical application, and an applet—using the plain JDK, a Java-enabled text editor, and a Java IDE.

Chapter 3 starts the discussion of the Java language. In this chapter, we cover the basics: variables, loops, and simple functions. If you are a C or C++ programmer, this is smooth sailing because the syntax for these language features is essentially the same as in C. If you come from a non-C background such as Visual Basic, you will want to read this chapter carefully.

Object-oriented programming (OOP) is now in the mainstream of programming practice, and Java is an object-oriented programming language. Chapter 4 introduces encapsulation, the first of two fundamental building blocks of object orientation, and the Java language mechanism to implement it—that is, classes and methods. In addition to the rules of the Java language, we also give advice on sound OOP design. Finally, we cover the marvelous javadoc tool that formats your code comments as a set of hyperlinked web pages. If you are familiar with C++, you can browse through this chapter quickly. Programmers coming from a non-object-oriented background should expect to spend some time mastering the OOP concepts before going further with Java.

Classes and encapsulation are only one part of the OOP story, and Chapter 5 introduces the other—namely, inheritance. Inheritance lets you take an existing class and modify it according to your needs. This is a fundamental technique for programming in Java. The inheritance mechanism in Java is quite similar to that in C++. Once again, C++ programmers can focus on the differences between the languages.

Chapter 6 shows you how to use Java’s notion of an interface. Interfaces let you go beyond the simple inheritance model of Chapter 5. Mastering interfaces allows you to have full access to the power of Java’s completely object-oriented approach to programming. After we cover interfaces, we move on to lambda expressions, a concise way for expressing a block of code that can be executed at a later point in time. We then cover a useful technical feature of Java called inner classes.

Chapter 7 discusses exception handling—Java’s robust mechanism to deal with the fact that bad things can happen to good programs. Exceptions give you an efficient way of separating the normal processing code from the error handling. Of course, even after hardening your program by handling all exceptional conditions, it still might fail to work as expected. In the final part of this chapter, we give you a number of useful debugging tips.

Chapter 8 gives an overview of generic programming. Generic programming makes your programs easier to read and safer. We show you how to use strong typing and remove unsightly and unsafe casts, and how to deal with the complexities that arise from the need to stay compatible with older versions of Java.

The topic of Chapter 9 is the collections framework of the Java platform. Whenever you want to collect multiple objects and retrieve them later, you should use a collection that is best suited for your circumstances, instead of just tossing the elements into an array. This chapter shows you how to take advantage of the standard collections that are prebuilt for your use.

Chapter 10 starts the coverage of GUI programming. We show how you can make windows, how to paint on them, how to draw with geometric shapes, how to format text in multiple fonts, and how to display images.

Chapter 11 is a detailed discussion of the event model of the AWT, the abstract window toolkit. You’ll see how to write code that responds to events, such as mouse clicks or key presses. Along the way you’ll see how to handle basic GUI elements such as buttons and panels.

Chapter 12 discusses the Swing GUI toolkit in great detail. The Swing toolkit allows you to build cross-platform graphical user interfaces. You’ll learn all about the various kinds of buttons, text components, borders, sliders, list boxes, menus, and dialog boxes. However, some of the more advanced components are discussed in Volume II.

Chapter 13 shows you how to deploy your programs, either as applications or applets. We describe how to package programs in JAR files, and how to deliver applications over the Internet with the Java Web Start and applet mechanisms. We also explain how Java programs can store and retrieve configuration information once they have been deployed.

Chapter 14 finishes the book with a discussion of concurrency, which enables you to program tasks to be done in parallel. This is an important and exciting application of Java technology in an era where most processors have multiple cores that you want to keep busy.

The Appendix lists the reserved words of the Java language.

Java comes with a large programming library, or Application Programming Interface (API). When using an API call for the first time, we add a short summary description at the end of the section. These descriptions are a bit more informal but, we hope, also a little more informative than those in the official online API documentation. The names of interfaces are in italics, just like in the official documentation. The number after a class, interface, or method name is the JDK version in which the feature was introduced, as shown in the following example:

Programs whose source code is on the book’s companion web site are presented as listings, for instance:

Listing 1.1 InputTest/InputTest.java