Java man is the name given to fossils discovered in 1891 at Trinil on the baks of the Bengawan Solo River in Eats Java , Indonesia , one of the first known specimens of Homo erectus . Java Man ( Homo erectus erectus ) is the name given to fossils discovered in 1891 at Trinil - Ngawi Regency on the banks of the Solo River in East Java , Indonesia , one of the first known specimens of Homo erectus .