Ruchira answered 6 years ago
The main theme is the decadence in the modern metropolis, i.e the commercialization, materialism of modern life. In this respect, Joyce's Dublin could be Eliot's London in The Wasteland or Paris and Boston in the Preludes, Baudelaire's Paris.
So you see, the priest who had died was a rich priest, had too much of money for a priest- enough money to give to charities. The books in his room express this same contradiction- a book about a police officer who was also a thief, a Romantic yet saintly treatment of a Queen and so on. The boy is sensitive and wants to transcend this materialism. Since religion has been materialized, the boy seeks his personal Holy Grail through Mangan's sister. But at the end of the story- he realizes that his love for her was nothing spiritual but physical, teen infatuation.
Conflicts are between the materialistic modern life and the boy's reaction to it- he imagines carrying his chalice through the hostile market place. There is also a conflict between the materialism of the indifferent world and the mask of spirituality that it wears- the rich priest, Mrs.Mercer 'selling' used stamps for some 'pious purpose.'
Within the boy, there is another conflict unknown to him- his romantic yearning for transcendence and yet his entrapment in physical attraction and therefore the narrative voice talks about 'foolish blood' and 'the serious business of life.'
Joyce does not offer a resolution.