Java Runtime Mac Install
The following are the system requirements for installing the JDK and the JRE on macOS:
Any Intel-based computer running macOS.
Administrator privileges.
You cannot install Java for a single user. Installing the JDK and JRE on macOS is performed on a systemwide basis for all users. Administrator privileges are required to install the JDK and JRE on macOS.
When you install the JDK, it also installs the JRE. However, the system will not replace the current JRE with a lower version.
To determine the current JRE version installed on your system, see Determining the JRE Version Installed on macOS. To install an earlier version of the JRE, you must first uninstall the current version. See Uninstalling the JRE on macOS.
When you install the JRE, you can install only one JRE on your system at a time. The system will not install a JRE that has an earlier version than the current version.
To determine the current JRE version installed on your system, see Determining the JRE Version Installed on macOS. To install an earlier version of the JRE, you must first uninstall the current version. See Uninstalling the JRE on macOS.
Note:
Installing a JRE from Oracle will not update
java -versionsymlinks or addjavato your path. To do this, you must install the JDK.
Java Runtime Environment Os X
Using the Command-line to find Java Versions - Mac. The Java Runtime (JRE) that you download from java.com or oracle.com contains a plugin to run Java content from your browser. In order to use the command line tools, you will need to download the Java Development Kit (JDK). The JRE and JDK are separate and can coexist on your system. Java Runtime Environment(JRE),适用于64位windows系统的Java环境，JRE是运行JAVA程序不可缺少的环境，拥有Java软件，您即会进入一个全新的互动世界,您可以免费下载。.
