Justice Munta Abimbola of the Oyo State High Court, who gave the sentence, said evidence showed that Adisa was guilty of the crime he was charged with.
He, however, discharged three other members of the union, Olumide Oladeji, Sadeeq Adejide and Tajudeen Arowotosuna, on the ground that there was no enough evidence linking them to the crime.
Court record said the medical student of ABU, Shannono, was shot dead and roasted on June 4, 2011, during a supremacy fight between factional groups of the union over the control of a motor park.
The deceased, who was said to be the President of the Medical Students Association of Nigeria, was in 500 level at the time of his death.
He was returning from a programme in Osogbo with some of his colleagues when he was killed.
Arowotosuna, who was discharged by the judge, brought his wife and a lawmaker as witnesses to prove that he was not at the scene of the crime when the medical student was killed.
He claimed that he was on his way to Abuja at the time to attend a burial.