Plato saw justice as
{ 1 } - treating others fairly.
{ 2 } - about human rights.
{ 3 } - divided into areas like distributive justice (which deals with the distribution by merit of wealth and honors) and corrective justice (which deals with punishment).
{ 4 } - the correct ordering of the parts of the soul, whereby the rational part guides the spirited part, and both together guide the appetites.
This leads to a healthy soul and a happy person.