Here's how:
* Their emptiness: The jars are described as being "empty" and "dusty." This physical emptiness mirrors the emotional void the boy feels as he faces the reality of his situation. His romantic fantasies about Mangan's sister are ultimately crushed by the harsh realities of life.
* Their potential: While empty, the jars are "great" and "full of the odour of old apples." This suggests a potential for something more, a sense of possibility that is ultimately unfulfilled. This parallels the boy's idealistic vision of Araby, which he hopes will offer him escape and adventure.
* Their irony: The boy initially imagines the jars as "treasure-chambers," full of exotic and beautiful objects. He believes he will find something special at Araby, like a "miracle." However, the bazaar is ultimately a disappointment, filled with tawdry goods and a sense of emptiness. This aligns with the emptiness of the jars, reflecting the irony of his unmet expectations.
In short, the two great jars in "Araby" serve as a powerful visual metaphor for the protagonist's disillusionment with the world and the fleeting nature of his dreams. They represent the gap between his idealistic vision and the harsh realities he confronts.