They could resolve all their disputes which led to Russo - Japanese war in the first place. Russians have built the railroad through Manchuria to Port Arthur and Japanese at the time just have consolidated their reign over Korea. The japanese diplomats then on couple of occasions came to Russia with the desire for defining their respective zones of influence in the region but Nicholas II Douche stalled and in the end even refused to see their diplomats. Japanese wanted for Russia to recognize the independence of Qing and Korean empires, with their mutual economic dominance over them, and retaining the right of Japan annexing Korea and Russia Manchuria.
In general they could be friends after the stated successful deal and then be united in anti - British/French efforts to evict them from China and Indochina.