Complex sentence: Appeals are considered the appropriate manner by which to challenge a judgment rather than trying to start a new trial, and once the appeals process is exhausted or waived, "res iudicata" will apply even to a judgment that is contrary to law.
Split into simpler sentences: Appeals are considered the appropriate manner by which to challenge a judgment rather than trying to start a new trial. Once the appeals process is exhausted or waived, "res iudicata" will apply even to a judgment that is contrary to law.