修改 ~/.bash_profile文件：

export JAVA_8_HOME=$(/usr/libexec/java_home -v1.8)
export JAVA_11_HOME=$(/usr/libexec/java_home -v11)

alias java8='export JAVA_HOME=$JAVA_8_HOME'
alias java11='export JAVA_HOME=$JAVA_11_HOME'

default to Java 11

java11

参考： https://blog.csdn.net/yuexiaomao/article/details/111057654

https://docs.oracle.com/en/java/javase/11/install/installation-jdk-macos.html#GUID-7EB4F697-F3D1-40EA-ACDF-07FA90F02D57