For those of us using the command line, you can use java_home to "pick" the JDK even though the Java Preferences app has been removed and without mucking with CurrentJDK (which is what I used to do until I found this trick). This can be used to set your JAVA_HOME such as adding the following to your ~/.bash_profile:
export JAVA_HOME=`/usr/libexec/java_home`
Assuming whatever you do uses JAVA_HOME (such as maven), your golden
By default, java_home returns the 'default', which is Java 7:
/Library/Java/JavaVirtualMachines/jdk1.7.0_09.jdk/Contents/Home
You can see all the possible options using -V:
> /usr/libexec/java_home -V
Matching Java Virtual Machines (5):
1.7.0_09, x86_64: "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_09.jdk/Contents/Home
1.7.0_07, x86_64: "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_07.jdk/Contents/Home
1.7.0_06, x86_64: "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_06.jdk/Contents/Home
1.6.0_37-b06-434, x86_64: "Java SE 6" /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
1.6.0_37-b06-434, i386: "Java SE 6" /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
Once you know what you have and which you want, you can specify:
/usr/libexec/java_home -d64 -v 1.6.0_37
Or to choose the latest installed 1.6.X:
/usr/libexec/java_home -d64 -v 1.6*
Check the man page for java_home for additional details