In Hertfordshire, Jack Worthing holds the position of Justice of the Peace (J.P.).
What Does This Mean?
As a Justice of the Peace, Jack is responsible for upholding the law and maintaining order in his community.
This adds to the irony of his double life, as he is supposed to be a pillar of respectability, yet he is living a lie by pretending to have a fictional brother named "Ernest."
Wilde uses this contrast to satirize Victorian hypocrisy, showing how even those in positions of moral authority are often deceiving others.