(Oakdale, MN)  —  A man has been sentenced to 18 years in prison for attacking a postal worker in Oakdale last summer.  The U.S. Attorney’s office says James Jackson Jr. repeatedly punched a worker who would not give him a package because his credentials did not match the needed information.  That person needed surgery for their hand while also suffering several scrapes, cuts, and bruises.  Investigators say they later found marijuana in the package.  Jackson, who was convicted of assault and attempted robbery, will also have to serve three years of supervised release.