Learning Java, 4th Edition

A Java Road Map

With everything that’s going on, it’s hard to keep track of what’s available now, what’s promised, and what has been around for some time. The following sections constitute a road map that imposes some order on Java’s past, present, and future.

The Past: Java 1.0–Java 1.6

Java 1.0 provided the basic framework for Java development: the language itself plus packages that let you write applets and simple applications. Although 1.0 is officially obsolete, there are still a lot of applets in existence that conform to its API.

Java 1.1 superseded 1.0, incorporating major improvements in the Abstract Window Toolkit (AWT) package (Java’s original GUI facility), a new event pattern, new language facilities such as reflection and inner classes, and many other critical features. Java 1.1 is the version that was supported natively by most versions of Netscape and Microsoft Internet Explorer for many years. For various political reasons, the browser world was frozen in this condition for a long time. This version of Java is still considered a sort of baseline for applets, although even this will fall away as Microsoft drops support for Java in its platforms.

Java 1.2, dubbed “Java 2” by Sun, was a major release in December 1998. It provided many improvements and additions, mainly in terms of the set of APIs that were bundled into the standard distributions. The most notable additions were the inclusion of the Swing GUI package as a core API and a new, full-fledged 2D drawing API. Swing is Java’s advanced user interface toolkit with capabilities far exceeding the old AWT’s. (Swing, AWT, and some other packages have been variously called the JFC, or Java Foundation Classes.) Java 1.2 also added a proper Collections API to Java.

Java 1.3, released in early 2000, added minor features but was primarily focused on performance. With version 1.3, Java got significantly faster on many platforms and Swing received many bug fixes. In this timeframe, Java enterprise APIs such as Servlets and Enterprise JavaBeans also matured.

Java 1.4, released in 2002, integrated a major new set of APIs and many long-awaited features. This included language assertions, regular expressions, preferences and logging APIs, a new I/O system for high-volume applications, standard support for XML, fundamental improvements in AWT and Swing, and a greatly matured Java Servlets API for web applications.

Java 5, released in 2004, was a major release that introduced many long-awaited language syntax enhancements including generics, typesafe enumerations, the enhanced for-loop, variable argument lists, static imports, autoboxing and unboxing of primitives, as well as advanced metadata on classes. A new concurrency API provided powerful threading capabilities, and APIs for formatted printing and parsing similar to those in C were added. RMI has also been overhauled to eliminate the need for compiled stubs and skeletons. There were also major additions in the standard XML APIs.

Java 6, released in late 2006, was a relatively minor release that added no new syntactic features to the Java language, but bundled new extension APIs such as those for XML and web services.

The Present: Java 7

This book includes all the latest and greatest improvements through the final release of Java 7. This release adds some minor language syntax enhancements such as those to improve exception handling and resource management. It also includes some major API updates, such as a completely new filesystem API and additions to many others.

This edition of the book is the first since the Java 5 release and therefore has been completely overhauled to incorporate all of the changes from the Java 6 and Java 7 releases.

Here’s a brief overview of the most important features of the current core Java API:

JDBC (Java Database Connectivity)

A general facility for interacting with databases (introduced in Java 1.1).

RMI (Remote Method Invocation)

Java’s distributed objects system. RMI lets you call methods on objects hosted by a server running somewhere else on the network (introduced in Java 1.1).

Java Security

A facility for controlling access to system resources, combined with a uniform interface to cryptography. Java Security is the basis for signed classes, which were discussed earlier.

JFC (Java Foundation Classes)

A catch-all for a number of features, including the Swing user interface components; “pluggable look and feel,” which means the ability of the user interface to adapt itself to the look and feel of the platform you’re using; drag and drop; and accessibility, which means the ability to integrate with special software and hardware for people with disabilities.

Java 2D

Part of JFC; enables high-quality graphics, font manipulation, and printing.

Internationalization

The ability to write programs that adapt themselves to the language the user wants to use; the program automatically displays text in the appropriate language (introduced in Java 1.1).

JNDI (Java Naming and Directory Interface)

A general service for looking up resources. JNDI unifies access to directory services, such as LDAP, Novell’s NDS, and others.

The following are “standard extension” APIs. Some, such as those for working with XML and web services, are bundled with the standard edition of Java; some must be downloaded separately and deployed with your application or server.

JavaMail

A uniform API for writing email software.

Java 3D

A facility for developing applications with 3D graphics.

Java Media

Another catch-all that includes Java 2D, Java 3D, the Java Media Framework (a framework for coordinating the display of many different kinds of media), Java Speech (for speech recognition and synthesis), Java Sound (high-quality audio), Java TV (for interactive television and similar applications), and others.

Java Servlets

A facility that lets you write server-side web applications in Java.

Java Cryptography

Actual implementations of cryptographic algorithms. (This package was separated from Java Security for legal reasons.)

JavaHelp

A facility for writing help systems and incorporating them in Java programs.

Enterprise JavaBeans

A component architecture for building distributed server-side applications.

Jini

An interesting distributed component technology that is designed to enable distributed computing, discovery, and rendezvous of devices ranging from software tools to hardware and household appliances.

XML/XSL

Tools for creating and manipulating XML documents, validating them, mapping them to and from Java objects, and transforming them with stylesheets.

Web services

Tools for creating and deploying Java-based SOAP web services.

In this book, we’ll try to give you a taste of as many features as possible; unfortunately for us (but fortunately for Java software developers), the Java environment has become so rich that it’s impossible to cover everything in a single book.

The Future

Changes in Java have become less frequent as Java has matured over the years, but Java continues to be one of the most popular platforms for application development. This is especially true in the areas of web services, web application frameworks, and XML tools. While Java has not dominated mobile platforms in the way it seemed destined to, the Java language and core APIs are used to program for Google’s Android mobile OS, which is used on billions of devices around the world. In the Microsoft camp, the Java-derived C# language has taken over much .NET development and brought the core Java syntax and patterns to those platforms.

Probably the most exciting areas of change in Java today are found in the trend toward lighter weight, simpler frameworks for business and the integration of the Java platform with dynamic languages for scripting web pages and extensions. There is much more interesting work to come.

Availability

You have several choices for Java development environments and runtime systems. Oracle’s Java Development Kit (JDK) is available for Mac OS X, Windows, and Linux. Visit Oracle’s Java website at for more information about obtaining the latest JDK. This book’s online content is available at http://oreil.ly/Java_4E.

There is also a whole array of popular Java Integrated Development Environments. We’ll discuss two in this book: IBM’s Eclipse and the Oracle NetBeans IDE. These all-in-one development environments let you write, test, and package software with advanced tools at your fingertips. While Eclipse is unquestionably the most popular and is open source, this author’s preferred IDE is Intellij IDEA by JetBrains, which now also has a free community edition.