anarchism includes within itself those who openly advocate the use of violence for social struggle and revolution and a radical pacifist section which opposes any type of violence called anarcho-pacifism as advocated by people like Leo Tolstoy, ammon Hennacy, Bart de Ligt and Dorothy Day which is also heavily influenced by Mohandas Gandhi (see http://en.wikipedia.org/wiki/Anarcho-pacifism
These two citations show the complexity of the issue within anarchism
"Anarchists are opposed to violence; everyone knows that. The main plank of anarchism is the removal of violence from human relations. It is life based on freedom of the individual, without the intervention of the gendarme. For this reason we are the enemies of capitalism which depends on the protection of the gendarme to oblige workers to allow themselves to be exploited--or even to remain idle and go hungry when it is not in the interest of the bosses to exploit them. We are therefore enemies of the State which is the coercive violent organization of society."
"And since the environment today, which obliges most people to live in misery, is maintained by violence, we advocate and prepare for violence. That is why we are revolutionaries, and not because we are desperate men thirsting for revenge and filled with hate....We must, in every way possible, and in accord with local conditions and possibilities, encourage action by associations, cooperatives, groups of volunteers — in order to prevent the emergence of new authoritarian groups, new governments, combating them with violence if necessary, but above all by rendering them useless. "