What is postulates of justice?

The postulates of justice is a term used in the legal field of Jurisprudence and relates with the relation of society, law and justice. To define justice is a hard task so the law rather concerns itself with "what justice should'nt be" instead of what it is. According to Voet law should be just and reasonable and ensures justice. A criteria for was formed with which the law has to comply with in order not to be unjust namely: Reasonableness, Generality, Equality, certainty and fair process