It is quite old topic but as every year I almost always forget the correct sequence on how to change my signed certificates in my used keystores I thought that maybe it would be nice to share a nice tutorial on how to do it with KeyStore browser.
Maybe someone in here will be interested and thankful if it comes up in forums search.
Download keystore browser here: http://keystore-explorer.org/downloads.html
Code42 has nice tutorial for usage with self-signed : https://support.code42.com/Administrator/5/Configuring/Create_a_signed_keystore_with_the_KeyStore_Explorer#Build_the_keystore
Existing certificates: https://support.code42.com/Administrator/5/Configuring/Create_a_signed_keystore_with_the_KeyStore_Explorer#Build_a_keystore_with_existing_key_materials
Cheers!
Thomas