Why does Dalvik not support swap space?

I was asked this question and also explain why it is detrimental to the android system as a whole. I have not found a web page which refers to this specific question about Dalvik and swap space. Any links would be appreciated or an explanation. What I have answered is Swap space is a method of using secondary storage of the device to free up RAM. This would not work on android as it is not guaranteed that a device would have secondary storage causing the application to crash. It is also slow to read from external storage as Dalvik is a JIT compiler this may lead to the code being compiled at a rate which is effecting the users experience with the app. > An initial decision of Dalvik was not to support swap space. Explain what swap space is and why it would be detrimental to the Android system as a whole.