Shulou(Shulou.com)06/02 Report--

This article mainly introduces "how to achieve the Java list". In the daily operation, I believe many people have doubts about how to realize the Java list. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts about "how to achieve the Java list". Next, please follow the editor to study!

Elliotte Rusty Harold, from New Orleans, is an associate professor of computer science at Polytechnic University, teaching Java and object-oriented programming. His Web site Cafe au Lait has become one of the most popular independent Java sites on Internet, and its sister site Cafe con Leche has become one of the most popular XML sites.

2007 will be a year in history, when Sun Microsystems will release the Java JDK under an open source license, giving up control of the Java ™platform and handing power to the Java developer community! In this article, Java developer Elliotte Rusty Harold predicts the new direction of the Java platform from scripting to bug fixes to new syntax.

2006 was another prosperous year for the Java platform. Despite the impact from Microsoft (C #) and the scripting language community (Ruby), Java remains the number one programming language in the world. At the same time, while the release of Java 6 is worth celebrating, it is overshadowed by the announcement that Java will be fully open source under GNU General Public License. Can Java maintain this momentum in 2007? Let's look at the possibility of success or failure.

Java platform will become an open source platform

In the first half of 2007, Sun will release the Java development kit (JDK) under an open source license agreement. Unlocking JDK is a huge step for the Java developer community, which will drive the development of the Java platform over the next decade.

The quality of JDK will be significantly improved because programmers will no longer just report bug and start fixing it. Java Developer Connection's bug report will include a detailed analysis of the problem section in JDK and provide fixes. As stated in Linus's law, "any bug is obvious as long as enough attention is given," that is, debugging can be done in parallel. The same is true of optimization. Open source enables the two to run side by side.

Branch project

Unfortunately, design can not be done in parallel with debugging and optimization. A clean API sometimes requires an authoritarian hand. But the disadvantage of dictators is that sometimes they know what they are doing and sometimes they don't. Competition between those who intend to be a dictator is often the only way to find the best solution to the problem.

Few companies can afford to develop multiple independent implementations of a product in order to choose to retain one of the products and abandon the rest, but the open source community is working in this direction. So, you'll find branch products at all levels of the Java platform: languages, virtual machines, and libraries. Most branch products fail, but it doesn't matter. Good ideas will stand out. Some branch products will exist forever, and some will be reintegrated into the standard JDK. By this time next year, the difference between branch products and mainstream products may not be obvious, but the process will continue.

Sun will start by releasing an early beta version of Java 7 Magi Dolphin in a few months' time. Sun cannot release an earlier version of JDK because there are build and license agreement issues that can only be resolved in Dolphin. Still, it is expected to see third parties begin to further break down Sun versions to provide popular open source implementations of Java 6, Java 5, Java 1.4, and even earlier.

Some of the early explorers of branch products might have infringed on Sun's trademark and received a nasty letter from Sun's lawyer. We need a generic name that is not registered as a trademark so that everyone can use it. I suggest "J"-I hope no one uses a single letter as a trademark.

Open source projects never die, but they fade. Like previous Blackdown Project, GNU Classpath, Kaffe, and other open source JDK projects, their developers are turning to something else. If a project has not reached 1.0 so far, it may never be achieved in the future.

Looking forward to Java 7

Dolphin will not be released in 2007. 2008 is a more realistic goal. That is to say, work is still under way, and some of its features may debut as early standard extensions or at least as beta.

Unfortunately, it is much easier to add functionality to a language than to remove it. Almost inevitably, with the passage of time, language does not develop in a simple direction, but becomes more and more complex and confusing. Even features that look good on their own can cause problems when superimposed on each other.

Unfortunately, the Java community did not learn this lesson, although the failure was not specific. But there are always neologisms that are too cool and exciting for neologism language designers to resist-even if such new grammars don't solve any practical problems. As a result, there are huge requirements for the new language features of Java 7, including closures, multiple inheritance, and operator overloading.

My guess is that by the end of the year, you'll see closures in Java 7 beta, and maybe operator overloading (with 50% certainty), but there won't be multiple inheritance. There is too much in Java based on the inheritance hierarchy of a single root. There is no feasible way to improve multi-inheritance to adapt to the language.

At present, there are many grammatical sugar proposals, some meaningful and some not. Many proposals focus on replacing methods like getFoo () with operators like->.

List

It is most likely to use array syntax to implement collection access. For example, the following code is no longer used:

List content = new LinkedList (10)

Content.add (0, "Fred")

Content.add (1, "Barney")

String name = content.get (0)

Instead, write the following code:

List content = new LinkedList (10)

Content [0] = "Fred"

Content [1] = "Barney"

String name = content [0]

Another possibility is to allow the use of array initializer syntax for lists. For example:

LinkedList content = {"Fred", "Barney", "Wilma", "Betty"}

Both proposals can be implemented by the compiler with a little magic without changing the virtual machine (VM), which is an important feature of any revised syntax. Neither of these proposals can invalidate or redefine any existing source code, which is a more important issue for the new syntax.

The features that really affect developer productivity should be built-in primitives for managing tables, trees, and mapping tables, such as those encountered when using XML and SQL. JavaScript's E4X project and Microsoft's C ω and Linq projects are pioneers in achieving this idea, but sadly, the Java platform seems to have missed this opportunity. If anyone wants to play a potential rescue game through the compiler, this is a good place not to be missed.

At this point, the study of "how to implement the Java list" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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