War in Europe had been feared since before the turn of the century.
Undercover makes a valid point. JWs write that war was unexpected and cherry-pick historical quotes regarding those who were hoping to create a Utopian society. They do this to try to bolster the concept that war was unexpected>therefore God must have caused it>therefore JWs must have had divine, special, advance knowledge.
However, war WAS expected. That is why European countries were furiously entering into mutual aid agreements with each other, and those multiple agreements are what pulled the world into war. Country A was attacked by Country Z. Country B had an agreement to support Country A, so they declare war on Z. Country Y has an agreement to support Country Z. When Country B declares war on Z as a result of its attack on A, Country Y has to get involved..etc...etc...
JWs do not quite know HOW to respond when I explain this to them and they discover that the WHOLE WORLD was expecting, and actively preparing, for war.