Justice has to do with laws
   → their enforcement
   → the penalty for violations

Fairness is a subjective term.   What is fair from one person`s perspective may be unfair from another`s.   

Example: A father has 2 sons.   One is profligate while the other is responsible.   The father determines to give the bulk of his estate to the responsible son while giving only a small financial award to the irresponsible one.   In most cases the profligate son would deem his father`s treatment to be unfair.   

Those of the communist persuasion would agree with the profligate son.   They would support his claim for an equal share of the estate.   

The Christian view is that the property belongs to the father.   It is his property to do with as he sees fit.   

Which is right?   

To answer that question we must consider the implications of the different treatments.   

Under the communist rule of fairness half the estate would be dissipated in short order by the profligate son leaving only half the wealth of the father remaining.   

Under the Christian rule of ownership the bulk of the estate would remain intact under the control of the son who would grow it.   The profligate son would end up in the same place as under the communist rule, just a little quicker.   

So, we see that the that the two critical issues are:
   → ownership
   → continuance

Who really owns the estate built by the father?   
   → the communist would say the state owns it
   → the Christian would say the father owns it

Who is concerned about continuance, i.e.   the future?   
   → the communist is preoccupied with today
   → the Christian has a concern for his grand-children

In this discussion the moral difference between communism and Christianity is clear.   

Justice and fairness aught not to be confounded.