打开终端，执行 /usr/libexec/java_home -V
MacBook-Air:~ eng$ /usr/libexec/java_home -V
Matching Java Virtual Machines (4):
1.8.0_101, x86_64: “Java SE 8” /Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home
1.7.0_79, x86_64: “Java SE 7” /Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/Home
1.6.0_65-b14-466.1, x86_64: “Java SE 6” /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
1.6.0_65-b14-466.1, i386: “Java SE 6” /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
/Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home
默认JDK1.6(Apple自带JDK)路径： /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
默认JDK1.7、1.8(Oracle) Home : /Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home
