Java installation manual

The entire process of JDK installation, and the method of verifying whether JDK is installed successfully.

1. JDK installation

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Custom jdk installation location

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install jre

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Customize jre installation location
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The installation is complete

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2. JDK installed successfully

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Use the command java -version to check whether the JDK is installed. After the installation is successful, the display is as follows:

Automatically generate the following folders

By default, the javac command is disabled.
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3. Configure environment variables

3.1. JAVA_HOME

new buildJAVA_HOME
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Create a new environment variable and click the OK button
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The effect is as follows:
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3.2. Java-related environment variables in Path

Create two new environment variables in Path

%JAVA_HOME%\bin

%JAVA_HOME%\jre\bin

Path already exists, click the Edit button.
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Click the New button
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Enter two environment variables respectively, and click the OK button.
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4. The environment variable configuration is successful

To check whether the environment variable is configured successfully, use javac -versionthe command

If the configuration is successful, javac related commands are already available
(note that the javac command can only be used normally after restarting cmd)
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5. Run the Java program

If the Java program can be run, it means that the JDK is installed successfully.

To run a Java program, you first need to generate a class file and then run it.

5.1. Create Java files

Java file example:
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HelloWorld.java code

public class HelloWorld {
    
    
    public static void main(String args[]) {
    
    
        System.out.println("Hello World!");
    }
}

5.2. Run javac command to generate class file.

cmd first enters the directory where the Java file is located. Use the following command:

javac 《Java文件全名》

Example run command:
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Generate class file effect:
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5.3. The effect of running the Java program

Run the Java program, the effect is as follows:
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