I can't find the location of jdk for Java 7 and 8

I have 3 different versions (jdk) of Java installed: 6, 7 and 8. In

bash_profile:

export JAVA_HOME=$(/usr/libexec/java_home -v 1.8)
setjdk() {
  export JAVA_HOME=$(/usr/libexec/java_home -v $1)
}

However, at

$ ls /System/Library/Java/JavaVirtualMachines
1.6.0.jdk

I see only one version. Where are the 2 other ones? What's the location of their jdks?