I was just looking at the JDK on my Mac with Mac OS X 10.7.3 and it looks like I have different versions of the JDK around. That's what I have Code: /Library/Java/JavaVirtualMachines/1.6.0_29-b11-402.jdk /Library/Java/JavaVirtualMachines/1.6.0_31-b04-411.jdk /System/Library/java/JavaVirtualMachines/1.6.0.jdk. Why do I find JDK under two different JavaVirtualMachines folders ? And why are there 2 different JDK under /Library/Java/JavaVirtualMachines ? I'm really confused. How can I check to which version I'm pointing ? Should I remove, and if yes what and how, redundant JDKs ?