Java beginners install jdk some problems

Please refer to my article to configure the JDK environment, any problem message:
https://blog.csdn.net/ArdenL/article/details/128865527

Also: Most JRE environments that Java open source frameworks rely on are indexed from JAVA_HOME, and many typical Java service frameworks are indexed directly from JRE_HOME.
If you make your own standard Java application(for example, a jar file that includes the java main method using only the standard java library), you can customize the dependency on HRE_HOME. Example: Java Server

This answer quotes ChatGPT

Yes, the JDK includes JRE, so after installing the JDK, you do not need to install an additional JRE.

When configuring environment variables, you need to be sure to add the JDK's "bin" folder Path to the "path" variable. Also, in order for the JDK to work, you need to add the JAVA_HOME system variable.

JAVA_HOME is a system variable that points to the JDK installation directory, for example, C:\Program Files\Java\jdk1.8.0_281. It is used to tell the system where to install the JDK. If you do not set JAVA_HOME in your environment variables, your Java application may not be able to find the JDK, resulting in a runtime error.

Adding %JAVA_HOME%\bin to the Path variable adds the JDK executable path to the system path. This will allow you to run commands such as the java compiler(javac.exe) and Java Virtual Machine(java.exe) from the command line without having to specify a full path.

Adding %JAVA_HOME%\jre\bin to the Path variable will allow you to run your Java application from the command line(for example, by using java commands) because it contains the Java runtime environment(JRE). This step is not necessary because the JDK already includes the JRE, but it can help ensure that the Java application has the correct runtime environment at runtime.

Therefore, the correct thing to do is to add JAVA_HOME to the system variable and %JAVA_HOME%\bin to the Path variable. If you want to run a Java application, you can also add %JAVA_HOME%\jre\bin to the Path variable.

1.JDK contains jre. You do not need to download jre.
2. Define the environment variable JAVA_HOME and add the first one to the system variable PATH.

JDK = JRE + development tool(such as Javac compiler)
JRE = JVM + Java SE jre is included in the standard class library
jdk.
If you only need to run java programs, just install the jre; However, to do development, you need to use the "development tool set", so you need to install the jdk.

Just learning java, you can check out the java video of Silicon Valley on Bilibili.

It is recommended that you use idea directly, idea can choose the JDK version, and then for your problem, generally, add the system variable is OK, The following two configurations are usually the default configurations in the default configuration file that comes with you.