Using Lazy Loading

The default persistence provider treats only OneToOne, ManyToOne, OneToMany, and ManyToMany mappings specially when they are annotated as LAZY. OneToMany and ManyToMany mappings are loaded lazily by default in compliance with the Java Persistence Specification. Other mappings are always loaded eagerly.

For basic information about lazy loading, see What You May Need to Know About EclipseLink JPA Lazy Loading.