I have searched several ways to change JDK version on mac.
$/usr/libexec/java_home
And I got
/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home
I tried
$export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home
also tried
/usr/libexec/java_home 1.8.0_31 --exec javac -version
then I run
$echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home
then I re-check java -version
$java -version
java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)
How I can really change java -version on my mac.