/usr/libexec/java_home
$ /usr/libexec/java_home -V
Matching Java Virtual Machines (2):
1.8.0, x86_64: "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home
1.7.0_51, x86_64: "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_51.jdk/Contents/Home
/Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home
export JAVA_HOME=$(/usr/libexec/java_home -version 1.7)