显示所有jdk版本
/usr/libexec/java_home -V

/usr/libexec/java_home -v 1.7
/Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home

/usr/libexec/java_home -v 1.8
/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home

/usr/libexec/java_home -v 11
/Library/Java/JavaVirtualMachines/jdk11.jdk/Contents/Home


下载 openjdk11

http://jdk.java.net/archive/

https://download.java.net/java/ga/jdk11/openjdk-11_osx-x64_bin.tar.gz

解压到 /Library/Java/JavaVirtualMachines


export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk11.jdk/Contents/Home

当前shell生效

java -version
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)

java -verbose