I'm trying to get the UID of my Galaxy S4 and i noticed that after turning on my S4 has a new UID.
Is there an option to set a static UID ?
Thanks in advance.
No, there is no API that permits you to set a static UID on the Galaxy S4.
However, depending on whether the Broadcom NFC controller supports this (there's no public information available about this) it might be possible to set a static anti-collision identifier when setting up the card emulation gate though NCI (NFC Controller Interface, see NFC Forum specifications). However, you would certainly need to create your own Android firmware with a modified libnfc-nci to do that.
UPDATE:
The Broadcom NFC controller does support setting arbitrary static UID values. See this answer for further information.