When you ask this question in relation to today's disputes, the universal answer is almost always arbitration. But it seems like this never completely seals the deal; one group seems to renege on the agreement at some point later on using the argument that the agreement was illegitimate since they really do own those territories so there's no legitimate way they could have been given away. See: Israel-Palestine.
So my question is do we, historically, have examples of groups settling territorial disputes in a way that both parties are satisfied and stay that way long term, or do grudges always continue and later erupt?
I guess one must ask as to how you define "resolved". For example, ownership of the Falklands islands was very much resolved after the 1982 war in that outside of some hot air, it is highly unlikely that Argentina is ever going to have another crack at them. Similarly, Japan's crack at China or Korea, though they both cause great dislike of the Japanese by both those nations, is unlikely to see a resurgence of Japanese aggression. Heinlein's quote against the phrase "violence never settles anything" is "tell the people of Hiroshima that." Even if an agreement is signed, it's often as a result of military force, or at least an acceptance that one side is a lot bigger than the other economically or militarily, so there is no point in even trying the military route, and the ownership becomes accepted without violence.
I guess one might make an argument for he Hong Kong handover. Not that the British ever truly claimed Hong Kong as integral territory, but return of control happens on schedule per agreement.