How to manage multiple JDK versions in Yosemite

See all installed java versions,  (Please note the capital V, simple v will be used later on for different purpose)

 /usr/libexec/java_home -V  

Outputs..

 Matching Java Virtual Machines (4):  
   1.8.0_25, x86_64:  "Java SE 8"  /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home  
   1.7.0_71, x86_64:  "Java SE 7"  /Library/Java/JavaVirtualMachines/jdk1.7.0_71.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  

Now you know whats available. All you need to do now is change your ~/.bash_profile to set JAVA_HOME. Before we do so, lets see how we can use /usr/libexec/java_home tool to retrieve JAVA_HOME paths of each versions.

Following command gives JAVA_HOME path of a given java version installed.

 /usr/libexec/java_home -v  

v1.8

  asanga@localhost:$ /usr/libexec/java_home -v 1.8  
 /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home  

v1.7

  asanga@localhost:$ /usr/libexec/java_home -v 1.7  
 /Library/Java/JavaVirtualMachines/jdk1.7.0_71.jdk/Contents/Home  

Now, lets add that trick to our ~/.bash_profile.

 export JAVA_HOME=`/usr/libexec/java_home -v 1.8`  
 #export JAVA_HOME=`/usr/libexec/java_home -v 1.7`  
 #export JAVA_HOME=`/usr/libexec/java_home -v 1.6`  

Now you can uncomment the version you need when you need.