Non-judicial punishment, or NJP for short, is reserved for minor violations of the UCMJ. If accused of committing a minor offense, a military service member may be offered non-judicial punishment (Article 15) at the discretion of his or her command. The service member may either choose to accept NJP or they can refuse and demand court-martial, instead.
Non-judicial punishment goes by a few different names depending on the branch of military in question. This includes Article 15, Captain’s Mast or Admiral’s Mast, and Office Hours.