But of course whether a state is neutral or non-aggressive, it still doesn't necessarily follow that their society is pacific and has eschewed violence. Both Sweden and Switzerland have long-declared traditions of international neutrality ... but both, in the absence of any military treaties or alliances with other states, maintain their own, quite formidable, armed forces. (Hasn't Sweden just reintroduced compusory military service? And I believe Switzerland has more firearms per head held by the civillian population, than does the notoriously gun-toting USA.)
Amongst modern European states the only one outside of micro-states (and even the Vatican, Monte Carlo and San Marino maintain military units) that doesn't have an army is Andorra. Andorra does have a dedicated "colour guard" unit of about two dozen policemen who are used for ceremonial functions, although about half of this force actually comprises the brass band. Andorra's gendarmes, perhaps like Costa Rica's, are actually well-armed and equipped, but they nevertheless have no offensive capability outside of their state's borders and their efforts are entirely focussed on tackling domestic crime, smuggling, illegal narcotics, counterfeit goods, and terrorism.
That said however, throughout the 20th century Andorra was actually at war for more years than many other European states. In support of their neighbour, France, Andorra declared war against Imperial Germany in August 1914. But other than restricting financial services, there wasn't really much they could do to support the allied war effort, and so inevitably WW1 rather passed them by. It was only in 1939 when France declared war on Germany that Andorra looked again into the matter ... only to find that, having never beeen invited to be a signatory to the Treaty of Versailles, that they were still formally at war with Germany. So a few days after France and Britain declared war on Germay, Andorra hastily concluded a belated peace treaty with the Nazis, and then immediately opted for neutrality.
But I guess that is the thing with peaceful societies who have chosen to avoid all war and violence ... they rarely last very long. Sadly they almost inevitably get taken advantage of, annexed, invaded, occupied or simply taken over by their more belligerant neighbours, and so cease to exist independently.