Java Web Learning Note Chapter I, Introduction to the Java language

Chapter One Introduction to the Java languagefirst, what is Java?

Java programming Language: Simple, fully object-oriented, distributed, interpretive, robust, secure and system-independent, portable, high-performance, multi-threaded, and dynamic programming languages.

Java can compose cross-platform applications, a generic term for the Java programming language and Java platform (i.e. Javaee,javame,java SE) introduced by Sun Microsystems in May 1995.

Since the advent of Java has been very popular, rapid development. Java technology, with its versatility, efficiency, platform portability, and security, is widely used in personal PCs, data centers, game consoles, science supercomputers, mobile phones, and the Internet, while owning the world's largest developer professional community.

Second, the history of Java

The Java was launched by Sun Microsystems in May 1995, co-developed by James Gosling and colleagues and formally launched in 1995 . Originally known as Oak, Java was designed for embedded chips in consumer electronics in the 1991. Renamed Java in 1995 and redesigned to develop Internet applications. Java implementation of HotJava browser (Java applet support) shows the charm of Java: Cross-platform, dynamic web, Internet computing. Since then, Java has been widely accepted and promoted the rapid development of the web, the common browser June support Javaapplet.

In 2010, Oracle acquired Sun Microsystems and Java became Oracle's products.

third, the Java system

Java consists of three systems:

Java SE (J2SE) (Java 2 Platform Standard Edition,java Platform Edition)

Java EE (Java 2 Platform, Enterprise Edition, Java Platform Corporate Edition)

Java ME (J2ME) (Java 2 Platform Micro Edition,java Platform mini version)

Iv. Java Development environment

Eclipse

MyEclipse

IntelliJ idea

JBuilder

Jdeveloper

Netbeans

JCreator

v. Operation of Java programs

A well-written Java program does not run directly in the system, but is run in a Java virtual machine. The Java Virtual machine is also known as the JVM (Java VM), which is part of the Java Runtime Environment, also known as the JRE (Java Runtime Environment).

You can run Java programs as long as the JRE is installed on your computer.

Vi. Introduction to JRE and JDK

Java source code is a *.java plain text file that can be written using any text compiler, but is not executable.

The JDK is a Java language development package that can program *.java files to executable Java programs.

The executable Java program requires the JVM to run.

The JRE contains the JVM.

The JDK contains the JRE.

1. JRE

JRE (Java Runtime Environment,java Runtime Environment), a collection of environments necessary to run Java programs, including the JVM standard implementation Home Java Core Class library. Java can only be run, but not Java compilation, debugging and so on.

The JRE has a standalone version, and if the pound needs to run a Java program, install the JRE.

2. JDK

The JDK (Java Development Kit) is the Java Language Software Development Kit (SDK). is a Java suite for Java developers to publish.

The basic components of the JDK include: compiler, jar packaging tool, Javadoc document generator, debug debugger, header file generator, anti-binder, monitoring tool, etc.

The JDK contains the full JRE. If the JDK is installed, you do not have to install the JRE again.

Reference: Geek College Course http://ke.jikexueyuan.com/zhiye/javaweb/

Java Web Learning Note Chapter I, Introduction to the Java language