Java is a programming language that originated in the the early 1990s Sun Company's Green project, the main purpose of which is to develop a distributed software system embedded in household appliances to make appliances more intelligent. Because the project team members are the Master of C + + (the age of the official C + + ERA), then use C + + for system development, but in the development process found that the characteristics of the C + + language itself caused by problems can not be effectively solved, such as: too complex, security and so on. The project team had to develop a small computer language in a "simple, reliable, compact and easy-to-transplant" framework to write programs in consumer electronics, which was named Oak.
Later, Sun company set up first person company for Green Project, in 93, WWW began to sweep the global background. First person company decided to relocate Oak. Turn it into the Web application area. When Oak was registered, it was found that the name was occupied and renamed Java. Why the name of Java, and now there are divergent opinions, we can search by themselves.
Java has a "form and feel" similar to the C + + language, but it is much easier to use than the C + + language, and it takes a "object-oriented" approach in programming, which is object-oriented programming. Java not only absorbs the various advantages of the C + + language, but also rejects the difficult to understand C + + inheritance, pointers and other concepts (multiple inheritance, as well as the advantages and disadvantages of pointers), so the Java language has a powerful and easy to use two features.
Brief introduction to Java development process:
- A project team called Green was established in 1991 to develop an object-oriented language called Oak.
- July 1994, Oak was applied to the World Wide Web.
- In the 1995, the boom in the internet gave oak opportunity. Sun first introduced an applet that could be embedded in a Web page that can be transmitted over the Web (an applet is a technique for embedding applets in a Web page to perform) and renamed Oak to Java
- In January 1996, Sun released its first Java Development Kit (JDK 1.0), an important milestone in Java's evolution, marking Java as a standalone development tool.
- JDK 1.1 was launched in February 1997.
- December 8, 1998, the second generation of the Java Platform Enterprise version of the EE published.
- In June 1999, Sun released the 3 versions of the second-generation Java platform (JAVA2): J2ME (mini-version of the JAVA2 Micro EDITION,JAVA2 platform) for mobile, wireless, and limited resources; J2SE (Java 2 Standard Edition,java 2 platform), applied to desktop environments, and Java EE (Enterprise Edition of the Java 2Enterprise Edition,java 2 platform), is applied to an application server that is based on the cloud.
- April 27, 1999, hotspot virtual Machine released. The hotspot virtual machine was released as an add-on to JDK 1.2, and later it became the default virtual machine for all versions of JDK 1.3 and later Sun JDK.
- In May 2000, JDK1.3, JDK1.4 and j2se1.3 were released in succession, and weeks later they were supported by Apple's industry standard for Mac OS x.
- September 24, 2001, j2ee1.3 released.
- February 26, 2002, j2se1.4 released.
- September 30, 2004, j2se1.5 released.
- In June 2005, at the Java One conference, Sun released the Java SE 6. At this point, various versions of Java have been renamed, and the number 2 has been canceled, as the JAVAEE,J2SE renamed Javase,j2me renamed to Javame.
- November 13, 2006, the inventor of Java technology, Sun, announced the release of Java technology as free software.
- Oracle announced its acquisition of Sun in 2009.
- In 2010, James Goslin, one of the co-founders of the Java programming language, resigned from Oracle Corporation.
- In 2011, Oracle held a global event to celebrate the launch of Java7, which was followed by Java7 's official release.
- In 2014, Oracle released the JAVA8 version of the company. (Details of development history)
Common Java Programming Tools:
- Eclipse: An open-source, Java-based, extensible development Platform [16].
- NetBeans: Open source Java integrated development environment for a variety of client and Web applications.
- IntelliJ idea: It has very good function in code automatic prompt, code analysis and so on. [17]
- [18] MyEclipse: A commercial software developed by Genuitec Corporation, which is a widely used Java application integration development environment.
- EditPlus: If the Java compiler "Javac" and the Interpreter "Java" are properly configured, you can execute the Java program directly using EditPlus compilation. (Analysis and comparison)
Java programming language Features:
- Simplicity: Go to statements are not supported, instead provide break and continue statements and exception handling, remove multiple inheritance features and pointers from C + +, eliminate the use of master files, eliminate preprocessor, automatically handle object references and indirect references, and automate the collection of useless units. So that users do not have to worry about storage management problems, more time and effort to spend on research and development.
- Object-oriented: Java is an object-oriented language. For programmers, this means paying attention to the data that should be in place and manipulating the data (method), rather than strictly using the process to think. are organized by class.
- Distribution: Java is designed to support application on the Web, and it is a distributed language. Java supports a variety of levels of network connectivity, and the socket class supports a reliable stream network connection, so users can generate distributed clients and servers.
- Compile and interpret: the Java compiler generates bytecode (Byte-code) instead of the usual machine code. Java bytecode provides an architecture-neutral destination file format that is designed to efficiently transfer programs to multiple platforms. Java programs can run on any system that implements the Java interpreter and the running system (Run-time systems).
- Robustness: Java is a strongly typed language that allows extensions of the ability to check for potential type mismatch problems at compile time, requires explicit method declarations to ensure that the compiler can catch call errors, does not support pointers, eliminates the possibility of overwriting stored and corruption data, and automatic "garbage collection" Prevent storage leaks and other harmful errors related to dynamic storage allocation and deallocation; the Java interpreter also performs many runtime checks, such as verifying that all arrays and string accesses are within bounds; exception handling, using the try/catch/finally statement, programmers can find the processing code of the error, This simplifies the task of error handling and recovery.
- Security: The storage allocation model for Java is one of its primary methods of defending against malicious code. Java has no pointers, so programmers can't get the hidden insider and forge pointers to the memory.
- Portability: The Java environment itself is portable for new hardware platforms and operating systems. The Java compiler is also written in Java, while the Java runtime system is written in Ansic language.
- High performance: Java is a language that is compiled and interpreted first, so it is not as fast as a fully compiled language. However, in some cases performance is very important, in order to support these situations, the Java designer to create a "timely" compiler, it can at runtime to translate Java bytecode into a specific CPU (central processing Unit) machine code, that is, the implementation of full compilation.
- Multithreading: Java is a multi-threaded language that provides support for multi-threaded execution (also known as a lightweight process) and can handle different tasks, making it easy to program with clues. The Java lang Packet provides a thread class that supports methods for starting clues, running clues, stopping clues, and checking the status of clues.
- Dynamic: The Java language is designed to adapt to a changing environment, which is a dynamic language. For example, classes in Java are loaded as needed, and even some are obtained over the network.
Java technology stack: First, Java programming language overview
