What is JPA's actual default FetchType for @ManyToOne and @OneToOne, and why does that surprise people?

EAGER — unlike @OneToMany and @ManyToMany, which default to LAZY. This is a common, genuine gotcha: developers who assume every association defaults to lazy loading are surprised to find @ManyToOne/@OneToOne associations loading eagerly on every parent fetch unless explicitly overridden to LAZY.