What is JDK
JDK is the Java Development Kit, a java development toolkit, developed by Sun Company.
Three versions of JDK
Java 2 Platform Standard Edition (J2SE) for small devices and smart cards (Java 2 Platform Micro Edition, J2ME) for server applications and services (Java 2 Platform Enterprise Edition)
The main contents of JDK
Java Tools Java Running Environment (Java Virtual Machine) - Basic Java Basic Class Library for Running Java Programs - Installation of the Basic JDK for Developing Java Applications
JDK is installed without installation, just download it from the official website.
JDK configuration
Enter the system environment variable dialog box:
1. Configure Java-HOME
1). Variables indicate the installation path of JDK. If not, create a new Java-HOME
2. Configure PATH
1). Add "%Java-HOME%bin;" to the front end of the variable value - this variable tells the location of the executable file corresponding to the Java command of the system)
2).%Java-HOME% means referring to the value of Java-HOME that has been configured in step 1.
3. Configure ClassPath
1.) Add ".;%Java-HOME%/lib/dt.jar;%Java-HOME%/lib/tools.jar" to the front end of the variable value - this variable is to set the classpath
2). Note: There is a point "." at the beginning of the string, which is also part of the path, representing the current path.
View the values of Path and ClassPath in DOS
In the system's dos command box, enter path to view the configured path, and enter set classpath to view the value of classpath.
What content does the folder under JDK contain
bin - contains executable files such as compilers and interpreters
db - built-in data Derby
demo--A demonstration program case containing source code
include - C language header file used for local computer
jre--The root directory of the Java running environment
simple - sample program
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