Well if you think as utopia as a "heaven" then it is obtainable.
That depends on whether or not one believes in any form of a "Heaven", and if so, how they personally define Heaven.
I personally don't believe in Heaven as a place so much as a state of being, when your spirit, soul, or simply the energy that allows you to live becomes a part of God. Once you are a part of God, you let go of your human consciousness. Thus, you would not even NEED a utopia. If you were there with a human consciousness...well, then, I suppose is MAY be utopia, or it may be so overwhelming that the mental and emotional stress is almost painful.
in the pursuit for a utopian society does justice play a role
I had to grab my copy of "The Republic of Plato" for this one, because I remembered that, interestingly enough, it opens up with a section about Justice. (Plato was, after all, the guy who "first" conceived of the idea of a utopia).
"The justice of the society would secure that each member of it should perform his duties and enjoy his rights."
For the Greeks "justice", most simply, meant something akin to "rightness".
Francis MacDonald Cornford says of the Greek idea of justice "As a quality residing in each individual, justice would mean that his personal life--or as a Greek would say, his soul--was correspondingly ordered with respect to the rights and duties of each part of his nature."
Thus, while today we think of justice as a mechanism by which we MAKE something right; the Greeks saw justice more as a way of being "right" or "in order".
Thus, if everyone in a society reached this state of "rightness", they would automatically form into a utopian society.
I said above:
Is [utopia] possible? Unless humans evolve spiritually, I seriously doubt it.
To be able to achieve that state of "rightness", of "justice" that Plato believed every Greek would have to have in order to form a Utopian society, we would need more spiritual growth than we have thus far.
I think the only people that could form a Utopian society (or rather, COULD have formed one) are people like Gandhi, Buddha, and Jesus. They were spiritually evolved enough that they could reach that state of "justice". However, having that state of justice, they would be unable or unwilling to tell other people "no, you can't join our Utopia", and with the addition of people without "justice" in this society, Utopia would fail.
So unless we as humanity manage to ALL reach that state of justice (which, I said before, would require us to evolve spiritually first), Utopia is not possible for us.