/usr/libexec/java_home -v ？？？不生效

升级完BigSur /usr/libexec/java_home -v 1.8 不生效

➜  ~ /usr/libexec/java_home -V
Matching Java Virtual Machines (3):
    15.0.1 (x86_64) "Oracle Corporation" - "Java SE 15.0.1" /Library/Java/JavaVirtualMachines/jdk-15.0.1.jdk/Contents/Home
    1.8.192.12 (x86_64) "Oracle Corporation" - "Java" /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home
    1.8.0_192 (x86_64) "Oracle Corporation" - "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_192.jdk/Contents/Home
/Library/Java/JavaVirtualMachines/jdk-15.0.1.jdk/Contents/Home
➜  ~ /usr/libexec/java_home -v 1.8
/Library/Java/JavaVirtualMachines/jdk-15.0.1.jdk/Contents/Home 

使用

man java_home

得到

OPTIONS
       -v or --version  version
              Filters the returned JVMs by version (as if JAVA_VERSION had been set in the environment). Example versions: "11.0", or "14.0.2".

问题是 我该如何设置JAVA_VERSION