In general, I would say that violence is not the answer and can sometimes only add to problems, but there are very rare cases, perhaps when a government is using violence against it's own people and no one else is standing up against them, but getting killed or attacked anyway where I would consider the use of violence to stop the oppression justified.
I do believe that violence is justified in civil disobedience. Though it may pose danger, this is the most effective way to show governments peoples disapproval of them. Violence can help overthrow governments and start a paradigm shift towards a different way of living, maybe a better way to life that is fair for the majority of the people or what the people are fighting for.
I think violence is bnot a good way to express disapproval because it has a bad connotation ant discredit the movement. Then we've seen a lot of exemples that we can change things without violence, like Gandhi or Thoreau did when he didnt pay his taxes for exemple. Thank you for reading!