I actually know a guy who served in the army but said that his religious beliefs would not allow him to fight in a war. Because of the conscription system in Finland and the fact that civilian service (362 days.) and the unarmed service (Basically, you serve in the military but do not carry a weapon and you get assigned to a position where a firearm is not necessary. Lasts 270 days.) lasts longer than the shortest military service (Depending on the training 180-362 days.) he felt that this was the easiest way to get it over.
Besides he did say that he doubts God has anything against him shooting at cardboard targets and running in the woods.
Also according to Finnish law in case of war he can refuse to carry a weapon and he will get the same treatment as those who did unarmed service.