What are the three JPA inheritance mapping strategies, and what's the core tradeoff between them?

Single Table (one table, a discriminator column, nullable columns for subtype-specific fields — fastest, no joins, but sparse columns), Joined (one table per subtype joined back to a base table — normalized, but requires a join to reconstruct a full entity), and Table Per Class (each subtype fully independent — no joins for one subtype, but polymorphic queries across all subtypes need a UNION).