java virtual machine-JVM⭐
____JVM (Java Virtual Machine): Java Virtual Machine, referred to as JIVM, is a hypothetical computer that runs all Java programs. It is the operating environment of Java programs and is one of the most attractive features of Java. The Java code we write runs on the JVM.
____Cross-platform
____Any software must run on the operating system, and the software we write in Java can run on any operating system. This feature is called the cross-platform feature of the Java language. This feature is implemented by JVM, the program we write runs on JVM, and JVM runs on operating system.
As shown in the figure, the Java virtual machine itself does not have cross-platform functions. There are different versions of the virtual machine under each operating system, and these different versions of the virtual machine (JVM) are not universal . Each JVM can only be used in a specific Only the Java program itself can be used universally.
JRE
____JRE (Java Runtime Environment): is the runtime environment of Java programs, including JVM and core class libraries required by runtime.
JDK
____JDK (Java Development Kit): is a Java program development kit, including RE and tools used by developers.
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We want to run an existing Java program, then just install JRE.
We want to develop a brand new Java program, so we must install the JDK.
Diagram of the relationship between the three Js
Download and installation of JDK
Go to the official website https://www.oracle.com/index.html to find Resources and click Software Download (Google browser recommends not to open the English translation, otherwise it may display an error) If
you find the java
page, it will automatically jump down, and then click Java ( JDK) for Developers
select the file download of the corresponding system, you can
pay attention to the installation folder path without spaces and Chinese
** This note is based on the creation of the b station learning video. Corresponding portal