$ /usr/libexec/java_home -V
Matching Java Virtual Machines (4):
    9.0.1, x86_64:  "Java SE 9.0.1" /Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home
    1.8.0_131, x86_64:  "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home
    1.8.0_121, x86_64:  "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home
    1.7.0_80, x86_64:   "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home

/Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home

$ JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home
$ echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home

$ java -version
java version "9.0.1"
Java(TM) SE Runtime Environment (build 9.0.1+11)
Java HotSpot(TM) 64-Bit Server VM (build 9.0.1+11, mixed mode)