Java application domain analysis

If you are a beginner or just beginning to learn java programming, you may think about exactly where Java programming is used? Apart from minecraft, you can't see games written in Java, can you? Desktop tools like Adobe Acrobat and Microsoft office software are not written in Java, even Linux or windows operating systems. So where do people use Java? Is there a real application in Java?

Well, in fact, you are not the first person to have questions about this. Many programmers who are beginning to learn Java or choose to learn Java as a programming language at the undergraduate stage will have this question. In fact, when you install Java on the desktop, you can know some answers. Oracle will tell you that more than 3 billion devices are running Java. Isn't that a huge number!

Many companies use Java in different ways. Many server applications are written in Java to process tens of millions of requests every day. High frequency trading systems are also written in Java, such as Lmax trading system, which is built on the online interprocess communication library (disruptor). In this article, we will know more exactly which type of projects are completed in Java, which main fields and departments Java is used in, and what role Java plays in the real world?

Life application in the real world

In the real world, Java is used in many places, from e-commerce websites to Android apps, from scientific applications to financial products, such as electronic trading systems, from games like minecraft to desktop applications like eclipse, NetBeans and IntelliJ, from open source resource libraries to J2ME apps, and so on. Let's look at these in more detail.

1. Android apps

If you want to know where Java applications are, you're not far from the answer. Open your Android phone or any app. They are completely written in Java programming language with Google Android API, which is very similar to JDK. Android just started a few years ago, but today many Java programmers are developers of android app. Incidentally, although our previous article mentioned how android app works, that is, Android uses different Java virtual machines and different packages, the code is still written in Java.

2. Server application in financial service industry

Java is widely used in financial service industry. Many global investment banks, such as Goldman Sachs, Citigroup, Barclays and Standard Chartered (Standard Chartered Bank of England) and some other banks use java to write front-end and back-end electronic trading systems, settlement, information confirmation systems, data processing projects and other projects. Java is used to write server-side applications, but most of them have no front-end. They receive data from one server (upper level), process the data and send it to other processing systems (next level). Java swing is popular because it can develop graphical user interface clients for traders, but now c# is rapidly replacing swing's market, which puts swing under pressure.

3. Website application

Java is also widely used in e-commerce and website development. You can use many restfull architectures, which are spring MVC and struts 2 0 and similar frameworks. Even simple servlets, JSPS and struts are popular in various government projects. Many websites of government, medical, insurance, education, national defense and other departments are built on Java.

4. Software tools

Many useful software and development tools are written and developed in Java, such as ecilpse, inetellij idea and netbans ide. I think these are the most frequently used desktop applications written in Java. As mentioned above, swing was once very popular in the client development of graphical user interface. Most of them are used in the field of financial services and investment banks. Although JavaFX is gradually becoming popular, it still cannot replace swing, and c# has replaced swing in most financial fields.

5. Trading system

The third-party trading system, a large part of the financial services industry, is also written in Java. For example, a popular trading system like Murex, which is used to link with many front-end banks, is also written in Java.

　　6、J2ME Apps

Although the arrival of IOS and Android almost killed the J2ME market, there are still many low-end Nokia and Samsung phones using J2ME. Once upon a time, most games and mobile applications were written using MIDP, CLDC, or J2ME platforms to apply to Android system J2ME is still popular in Blu ray, magnetic card, set-top box and other products. The reason why app is so popular is that app is still applicable to J2ME for all Nokia phones.

7. Embedded field

Java also has great applications in the embedded field. You only need 130kb to use Java Technology (on a small chip or sensor), which shows how reliable this platform is. Java was originally designed for embedded devices. In fact, this is also part of the original "write now, run anywhere" theme of Java.

8. Big data technology

Hadoop and other big data technologies also use java to varying degrees, such as Apache's Java based HBase, Accumulo (open source) and elasticsearch. However, Java does not occupy the whole field, and other big data technologies, such as mongodb, are written in C + +. If Hadoop and elasticsearch develop gradually, Java can have the potential to get greater development space in the field of big data technology.

9. High frequency trading

The Java platform has greatly improved performance features and jits, and Java also has transmission performance at the C + + level. Therefore, Java is also popular for writing high concurrency systems. Although the transmission performance of Java is no better than that of C + +, you can not consider the security, portability and maintainability of Java (which has been implemented in Java), and Java has a faster running speed. Security and other problems will make the application written by an inexperienced C + + programmer slower and unreliable.

10. Scientific application

Now Java is often the default choice for scientific applications, including natural language processing. The main reason is that Java is more secure, portable and maintainable than C + + or other languages, and Java has better advanced concurrency tools.

In the 1990s, Java played an important role in the Internet due to applets. However, in recent years, applets have become more and more popular because of various security risks in the sandbox model of applets, resulting in the disappearance of almost all desktop Java and applets. However, Java is still the default application development language in the software industry, and it is widely used in the fields of financial services, investment banking and e-commerce. Anyone who studies Java thinks he has a bright future. And Java 8 reinforces the concept that Java will continue to dominate software development in the coming years.

summary

This article stops introducing the application field of Java programming. I hope it will be helpful to your future development planning.