What are the notions of the character such as hero and villain, antagonist and protagonist, in the story "Araby"?
In "Araby," the final story of the childhood section in James Joyce's Dubliners, the unnamed narrator is the story's protagonist, who sees himself as a modern knight going off to the crusades to bring something back for his friend's sister, with whom he is in love. He sees himself as the hero who carries this girl's name through the noisy Dublin streets imagining "that I bore my chalice safely through a throng of foes."
This hero goes off to the aptly-named Araby (where knights went during the Crusades) bazaar where he plans to buy this girl something and win her heart. Unfortunately for the boy, he meets his antagonist and the story's (childhood's?) villain: reality.
The boy arrives at the marketplace just before close because of the challenges and tribulations he has had to face (his uncle came home late and drunk and there was an "intolerable delay" at the train station). He runs into the market and sees, to his horror, a single stall still open, where a young English woman he has never seen before is flirting with two men. When the woman speaks to the boy out of "a sense of duty," he declines to buy anything and has an epiphany that he has made a fool of himself.
He leaves the bazaar in angry tears and chastises himself as "a creature driven and derided by vanity."
The word notion as used in your question is a bit unclear, so I will provide a response based upon using the literary terms mentioned to discuss the main character in “Araby”. In the story, the narrator is the most important character. As a result, he can be viewed as the protagonist (the principle character in a literary work). The narrator can also be called the antagonist (the main character’s opponent) if the conflict in the story is viewed as an inner struggle (a struggle that takes place within the character’s mind). The main character cannot really be classified as a hero or villain since heroes are generally characters who shows great courage or is admired for bravery and villains are characters who are evil or who do evil things. Since the narrator's actions of seeing the girl, talking to her, and going to the bazaar can be viewed as a sort of journey, the character can be viewed as dynamic (a character that experiences change in the story) rather than flat (a character that does not change and who is described in a limited way by the author).