Since you didn't specify whether it is upper or lower, two wheel drive or four wheel drive or any other particulars, I am going to have to give a general answer. It appears that they are pressed in and retained by a snap ring. If you have a local auto parts store that loans or rents tools you can obtain a ball joint press from them. Other things besides normal tools you will need are a Ball Joint separator and snap ring pliers.
Answers & Comments
Since you didn't specify whether it is upper or lower, two wheel drive or four wheel drive or any other particulars, I am going to have to give a general answer. It appears that they are pressed in and retained by a snap ring. If you have a local auto parts store that loans or rents tools you can obtain a ball joint press from them. Other things besides normal tools you will need are a Ball Joint separator and snap ring pliers.