Well-off will accompany you to learn the key features of JAVA---JAVA, java features

Well-off will accompany you to learn the key features of JAVA---JAVA, java features

Today, I started my blog journey. As a beginner, I would like to use this series to learn JAVA, a widely recognized basic programming language.

First, let's take a look at several key features of JAVA (optional ):

1. Concise and effective

Java is a simple "Object-Oriented" programming language. C ++ is omitted in Java.

All obscure and confusing features, such as header files, pointers, structures, units, and operators.

. It is more rigorous and concise.

 

2. Portability

For a programmer, if the written program does not need to be modified,

Running on MacOS, UNIX, and other platforms is a good thing for the dream! The Java language makes the original

It's getting closer and closer. Only a few modifications or even

Sometimes it can run on different platforms without modification.

 

3. Object-oriented

So it can be said that "object-oriented" is a revolution in software engineering, which greatly enhances human software development capabilities. It is a great progress and a major milestone in software development. In the past 30 years, "object-oriented" has developed considerably, fully reflecting its own value, so far, we have formed a complete system that includes "Object-Oriented System Analysis", "Object-Oriented System Design", and "object-oriented program design. Therefore, as a modern programming language, Java is no exception.

 

4. interpreted type

Java is an interpreted language. Compared with C/C ++, It is a program written in Java.

Low Efficiency and slow execution speed. However, by running the Java interpreter on different platforms

To achieve the grand goal of "writing once and running everywhere. To achieve the goal, sacrifice Efficiency

It is worth it. Moreover, the current computer technology is changing with each passing day, and the computing speed is getting faster and faster.

It's too slow.

 

5. Suitable for Distributed Computing

The Java language has powerful and easy-to-use networking capabilities and is very suitable for developing distributed computing programs.

Java applications can access remote objects through URLs as they access local file systems. Writing a Socket communication program in Java is very simple. It is easier to use it than to use any other language. It is also very suitable for the development of Common Gateway Interface (CGI) scripts. In addition, you can also use Java Applet and Java Server Page (JSP) servlet and other means

To build richer web pages.

 

6. Good Performance

As mentioned above, Java is an interpreted language, so its execution efficiency is relatively slow,

However, the Java language uses two methods to improve its performance.

A. After the Java source program is compiled, use the Java pseudo compiler for pseudo compilation to convert it into an intermediate

(Also known as bytecode;

B. Provides a quasi-real-Time (Just-in-Time, JIT) compiler.

Use the JIT compiler to convert bytecode to machine code, and then buffer it, which will be faster.

 

7. robustness and Prevention

During pseudo-compilation, the Java language has checked many early potential problems and made some

The corresponding check can be said to be the strictest "compiler ".

It's "preventing problems before them" means to throw errors in many programs into the blue. There are often

Errors that are exposed only when they are run in other languages are discovered during the compilation phase.

In addition, the Java language has many stable and robust features to effectively reduce errors.

This makes Java applications more robust.

8. multi-thread processing capability

Thread is a lightweight process and an essential feature in modern programming. Multithreading

Capability enables the program to be more interactive and real-time.

Java has superior performance in multi-thread processing and has powerful functions that surprise designers.

It is easy to process multiple threads.

 

9. High Security

Java has made a lot of research in terms of security during the design, which makes Java

Language is currently the safest programming language.

Despite Sun's promise that "using Java to easily build anti-virus and anti-hacker systems ",

But the truth "there is no absolute security in the world" will not fail to be verified because of someone's promise. Shortly after the release of JDK (Java Development Kit) 1.0, a group of security experts from Princeton (Princeton) University in the United States found the first error in Java 1.0 security features. Since then, Java security issues have been concerned. However, the security risks discovered so far are negligible, and the Java Development Team also claims that they pay great attention to the Bugs in system security and will immediately fix these detected buckets.

In addition, Sun has opened the Java interpreter details, so it is helpful to share

Prevent and stop these security risks.

 

10. It is a dynamic Language

Java is a dynamic language, which involves the following two aspects:

A. in Java, you can easily and intuitively query runtime information;

B. Add the new code to a running program.

 

11. It is a neutral structure

"The Java compiler generates a neutral object file format ." That is to say, the Java compiler uses

After pseudo-compilation, a "neutral" bytecode irrelevant to any computer system is generated.

This neutral structure was not the first in Java. Before the emergence of Java, the UCSD Pascal system had

This is done in a commercial product, and there is a precedent for this method before UCSD Pascal.

Niklaus Wirth is implemented in Pascal, which reduces some performance in exchange for better portability.

And universal methods.

 

This bytecode of Java has been carefully designed to be well compatible with most of today's

Popular computer systems are easy to interpret on any machine and can be translated into machine code dynamically.

I just started to learn java: ORA-00926: Missing VALUES keyword gb_seq is the sequence name in Oracle, ask that the field has a problem?

Insert into xxx (xx, xx, xx) values (?,?,?) This format

How to Learn java? -Chengdu longvo education java training to teach you

To learn Java well, you must first understand the general classification of Java. We know that since Sun launched Java, it has made every effort to make it all-encompassing. Therefore, since its development, Java has been divided into three main parts by application: J2SE, j2-and J2EE, this is the Sun ONE system. J2SE is the standard version of Java2 and is mainly used for programming desktop application software. J2SE is mainly used for embedded system development, such as mobile phone and PDA programming. J2EE is the Enterprise Edition of Java2, it is mainly used for the development of distributed network programs, such as e-commerce websites and ERP systems. Compared with traditional development languages such as VC, VB, and DEPHI, J2SE does not seem to have obvious advantages in developing desktop applications. For beginners, it seems a bit esoteric, and it is difficult for developers to have a development environment. So J2EE is the most widely used and best to learn. It is not a day or two to learn. So how can we learn J2EE? Of course, I/O, Util, and Lang are all familiar with Java syntax? And then learn from JSP. If you have learned HTML, there are a lot of things to do. If not, you can add the HTML basics. In fact, there are not many Java syntaxes in JSP. It is more like a scripting language, a bit like ASP. Then you should learn Servlet. Servlet is a server-side applet that generates HTML files sent to the client. During execution, JSP is converted to Servlet before running. Although JSP can completely replace Servlet in theory, this is also the intention of SUN to launch JSP, but Servlet is very convenient to control the process jump, it also makes the program clearer. Next, you should learn about Javabean. Maybe you have long looked at the confusing way JSP embeds Java code in HTML. What is the difference between this method and ASP? Fortunately, SUN provides Javabean to encapsulate the Java code in your JSP to facilitate calls and reuse. The next step is EJB, and EJB is the Enterprise JavaBean. The name seems to be a Javabean, but it is different from the Javabean. It is an architecture where you can build safer and more stable enterprise applications. A large amount of code has been completed by middleware (also known as Weblogic and Websphere J2EE servers), so the amount of code we need to do is small, most of the work is on designing and configuring middleware. As for JDBC, I don't need to talk about it. If you have compiled a program to access the database in java, you should be familiar with it. Also, if you want to compile a program for sending emails in Java, you have to look at Javamail. Well, after having some basic concepts of Java and J2EE, you should compile some programs and never talk about them on paper. It is best to look for some books with examples and CDs, so that you can directly Ctrl + C and then Ctrl + V if you see a good program, and you don't have to bother yourself to lose it again, besides, you don't have to worry about making mistakes when copying data directly. Why not! There are also some good Java programming articles that need to be Cut down. If you have any questions, even if the question is not too silly, the experts will answer you. So I read the book and the program. I can solve all the questions asked by others. Is it true that I have become a master? Of course it is not that simple. This is only the first step after the long journey. Believe it? Then, if you go out to pick up a project, do you know how to do it, do you know how to design it, and how to organize personnel for development? There may be nothing else in your mind except some scattered code! What you lack most is actual work experience, rather than the programs created out of thin air in books. So you should go to a Java programming job and improve yourself in practice, which is the fastest. Another way is to read the open source code program. We know that open source code is mostly from experts. They are well-designed and considerate. Coupled with the participation of a large number of programmers, the value of code is naturally a powerful word. Two open-source programs required to learn Java are Jive and Pet Store .. J... the remaining full text>