  We study three and four jet production in hadronic collisions at
next-to-leading order accuracy in massless QCD. We cross check results
previously obtained by the BlackHat collaboration for the LHC with a
centre-of-mass energy of sqrt(s)=7 TeV and present new results for the LHC
operating at 8 TeV. We find large negative NLO corrections reducing the
leading-order cross sections by about 40-50%. Furthermore we observe an
important reduction of the scale uncertainty. In addition to the cross sections
we also present results for differential distributions. The dynamical
renormalization/factorization scale used in the calculation leads to a
remarkably stable K-factor. The results presented here were obtained with the
NJet package, a publicly available library for the evaluation of one-loop
amplitudes in massless QCD.
