????Mac??Java??汾??1.7??
????java -version
????java version "1.7.0_71"
????Java(TM) SE Runtime Environment (build 1.7.0_71-b14)
????Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01?? mixed mode)
?????????1.8?汾?????Java -version??????????????1.7?汾?????????л???1.8?汾????????????????????ɡ?
????export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_40.jdk/Contents/Home/
????export PATH=$JAVA_HOME/bin:$PATH
????????????????????java -version???
????java -version
????java version "1.8.0_40"
????Java(TM) SE Runtime Environment (build 1.8.0_40-b27)
????Java HotSpot(TM) 64-Bit Server VM (build 25.40-b25?? mixed mode)
???????????Ч???????????????profile????С?
????echo 'export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_40.jdk/Contents/Home/' >> ~/.bash_profile
????source ~/.bash_profile