Picking up where the authors' first volume on Java
left off, Core Java 2, Volume 2
covers the more advanced features of the Java 2 platform that can add polish and power to your Java programs. The authors' accessible--yet thorough--coverage of essential Java APIs help make this book an attractive choice for any working Java developer.
Several chapters here are especially useful for getting control of new and important Java 2 features. Sections on the new Java 2 collection classes and using advanced Swing classes (like tables and trees) are particularly good. (While many other books just list Swing APIs, this volume provides short examples and effective commentary, which will let you master these complex Swing controls.) When it comes to Java2D graphics, the authors do a nice job of comparing the old AWT to the new Java2D, including drawing basic shapes and doing text output. (These operations are surprisingly tricky in this new API). A section on the new JDBC 2 standard shows off new features like ResultSets and scrollable cursors to good effect.
More advanced topics include multithreading, internationalization, and security. Throughout, this text introduces important concepts illustrated with comprehensible examples. The APIs for individual classes are listed too, making it possible to use this book as a reference, but it is the tutorial sections that stand out here. (The authors also aren't afraid to point out where Java 2 is lacking--for example, in its printing support.)
Readers of the first volume will naturally want the second volume of Core Java 2 too. It's also a great choice for any Java developer with JDK 1.1 experience who wants a tour of new Java 2 features that are essential for serious corporate development. --Richard Dragan
Topics covered: Java 2 advanced APIs, multithreading and synchronization, Java 2 collections, networking, databases and JDBC 2 (cursors and result sets), RMI and remote objects, Swing user interface classes, printing, tables and trees, JavaBeans, security and deployment, internationalization issues, JNI and native methods.
To the reader
The book you have in your hands is the second volume of the fourth edition of Core Java. The first edition appeared in early 1996, the second in late 1996, and the third in 1997/1998. The first two editions appeared in a single volume, but the second edition was already 150 pages longer than the first, which was itself not a thin book. When we sat down to work on the third edition, it became clear that a one-volume treatment of all the features of the JavaTM platform that a serious programmer needs to know was no longer possible. Hence, we decided to break up the third edition into two volumes. In the fourth edition, we again organized the material into two volumes. However, we rearranged the materials, moving streams into volume 1 and collections into Volume 2.
The first volume covers the essential features of the language; this volume covers the advanced topics that a programmer will need to know for professional software development. Thus, as with the first volume and the previous editions of this book, we still are targeting programmers who want to put Java technology to work on real projects.
Please note: If you are an experienced developer who is comfortable with the new event model and advanced language features such as inner classes, you need not have read the first volume in order to benefit from this volume. (While we do refer to sections of the previous volume when appropriate and, of course, hope you will buy or have bought Volume 1, you can find the needed background material in any comprehensive introductory book about the Java platform.)
Finally, when any book is being written, errors and inaccuracies are inevitable. We would very much like to hear about them. Of course, we would prefer to hear about them only once. For this reason, we have put up a web site at horstmann/corejava.html with an FAQ, bug fixes, and workarounds. Strategically placed at the end of the bug report web page (to encourage you to read the previous reports) is a form that you can use to report bugs or problems and to send suggestions for improvements to future editions. About This Book
The chapters in this book are, for the most part, independent of each other. You should be able to delve into whatever topic interests you the most and read the chapters in any order.
Chapter 1 covers multithreading, which enables you to program tasks to be done in parallel. (A thread is a flow of control within a program.) We show you how to set up threads and how to make sure none of them get stuck. We put this knowledge to practical use by example, showing you the techniques needed to build timers and animations.
The topic of Chapter 2 is the collections framework of the Java 2 platform. Whenever you want to collect multiple objects and retrieve them later, you will want to use a collection that is best suited for your circumstances, instead of just tossing the elements into a Vector. This chapter shows you how to take advantage of the standard collections that are prebuilt for your use.
Chapter 3 covers one of the most exciting APIs in the Java platform: the networking API. Java makes it phenomenally easy to do complex network programming. Not only do we cover this API in depth, we also discuss the important consequences of the applet security model for network programming.
Chapter 4 covers JDBCTM, the Java database connectivity API. We show you how to write useful programs to handle realistic database chores, using a core subset of the JDBC API. Please note that this is not a complete treatment of everything you can do with the rich JDBC API. (A complete treatment of the JDBC API would require a book almost as long as this one.)
Chapter 5 covers remote objects and Remote Method Invocation (RMI). This API lets you work with Java objects that are distributed over multiple machines. We also show you where the rallying cry of "objects everywhere" can realistically be used.
Chapter 6 contains all the Swing material that didn't make it into volume 1, especially the important but complex tree and table components. We show the basic uses of editor panes and the Java technology implementation of a "multiple document" interface. Again, we focus on the most useful constructs that you are likely to encounter in practical programming, since an encyclopedic coverage of the entire Swing library would fill several volumes and would only be of interest to dedicated taxonomists.
Chapter 7 covers the Java 2D API that you can use to create realistic drawings. The chapter also covers some advanced features of the Abstract Windowing Toolkit (AWT) that seemed too specialized for coverage in Volume 1 but are, nonetheless, techniques that should be part of every programmer's toolkit. These features include printing and the APIs for cut-and-paste and drag-and-drop. We actually take the cut-and-paste API one step further than Sun Microsystems itself did: We show you how to cut and paste serializable Java objects between different programs in the Java programming language via the system clipboard.
Chapter 8 shows you what you need to know about the component API for the Java platform-JavaBeansTM. You will see how to write your own beans that other programmers can manipulate in integrated builder environments. (We do not cover the various builder environments that are designed to manipulate beans, however.) The JavaBeansTM component technology is an extraordinarily important technology for the eventual success of Java technology because it can potentially bring the same ease of use to user interface programming environments that ActiveX controls give to the millions of Visual Basic programmers. Of course, since these components are written in the Java programming language, they have the advantage over ActiveX controls in that they are immediately usable across other platforms and capable of fitting into the sophisticated security model of the Java platform.
In fact, Chapter 9 takes up that security model. The Java platform was designed from the ground up to be secure, and this chapter takes you under the hood to see how this design is implemented. We show you how to write your own class loaders and security managers for special-purpose applications. Then, we take up the new security API that allows for such important features as signed classes.
Chapter 10 discusses a specialized feature that we believe can only grow in importance: internationalization. The Java programming language is one of the few languages designed from the start to handle Unicode, but the internationalization support in the Java platform goes much further. As a result, you can internationalize Java applications so that they not only cross platforms but cross country boundaries as well. For example, we show you how to write a retirement calculator applet that uses either English, German, or Chinese-depending on the locale of the browser.
Chapter 11 takes up native methods, which let you call methods written for a specific machine such as the Microsoft Windows API. Obviously, this feature is controversial: Use native methods, and the cross-platform nature of the Java platform vanishes. Nonetheless, every serious programmer writing Java applications for specific platforms needs to know these techniques. There will be times when you need to turn to the operating system's API for your target platform when you are writing a serious application. We illustrate this by showing you how to access the registry functions in Windows.Definitions
A Java object is an object that is created by a program that was written in the Java programming language.
A Java application is a program that was written in the Java programming language and that is launched by a Java virtual machine (that is, a virtual machine for the Java platform).