"3"java Development Environment Construction

1 , JRE and JDK the concept

What is a JRE and JDK?

　　　　JRE (Java runtime Environment-java running environment). All Java programs must be run under the JRE. It includes the JVM (Java Virtual machine) and the Java Core Class library.

JDK (Java Development Kit-java Development Kit). It is the core of the entire java. Includes the Java Runtime Environment, Java development Tools (Javac, Java, Javadoc, etc.) and the Java base Class library.

Summary: With JDK　　　　 instead , the JRE does not contain development tools, compilers, debuggers, and other tools. Developing Java Programs installs the JDKand runs the Java program to install the JRE .

2 , JDK Download and Anatomy of

JDK Download

　　　　official address:www.oracle.com or www.sun.com

Download Install: Open Oracle official website, find download-Popular download, then click Java Developer Tools –jdk Download – agree to the License agreement, choose your own PC version to download EXE installation package, x86 is a 32-bit operating system, x64 is a 64-bit operating system. Double-click Open, all the way to the next fool-type installation, the installation will note the installation path (should be installed in the name of no space, plain English and shallow path, where the default installation, general development no problem).

JDK anatomy

BIN:JDK contains some development tools to execute files

DB: An open source Java-developed relational database Derby

Include:c Language header file, support programming with Java local interface

root directory of the Jre:java Runtime Environment (JRE)

Lib:java Some library files to be used by the development tools (non-core class libraries Tools.jar, Dt.jar, etc.)

Src.zip: Archived Java source code

3 , Java Development Environment Configuration

Configuring Environment variables

When you execute the command java–version (show Java Version) command in a command-line window, the following error message appears:

This is because the currently executing Java command cannot be found under the path provided by the current path and PATH environment variable, so in order to recognize the Java Development command under any path, we can set its PATH environment variable in the Windows system. Add the JDK installation path \ bin path to the PATH environment variable.

The following is the system variable, there is edit, none is new, above is the name, the following is the value:

Path
%java_home%\bin;
(added to the front of the original data, this will first retrieve this directory, this variable is followed by the English semicolon!) ）

Java_home
C:\Program files\java\jdk1.8.0_131

CLASSPATH
.; %java_home%\lib\dt.jar;%java_home%\lib\tools.jar;%java_home%\lib

Tip: There are two ways to configure environment variables: Permanent configuration and temporary configuration methods

commands for temporarily configuring environment variables under DOS:

To view variables:
Set path

To set a variable:
Set path= variable Value

Add variables to the front:
Set path= variable value;%path%

Common Java Development environments

Text editor: Notepad, EditPlus, UltraEdit

Integrated development Environment (IDE):Eclipse, JBuilder, NetBeans

Eclipse

　　　　www.eclipse.org

"3"java Development Environment Construction