Lazy loading loads eager anyway ?

Question

Hello,
I read in some articles and books that the lazy loading in EJB 3.0 is just a hint, in the sence that the persistence manager could decide to load eager, even if lazy configured.
Is this correct, or will the default lazy loading always only fetch when asked ?
C.

Answer 1

This is true in the JPA Spec, i.e. meaning that supporting lazy loading is "optional" not required by the JPA Spec.
However TopLink does support lazy loading. By default any @OneToMany or @ManyToMany mappings are lazy and will not be fetched until accessed. By default in the JPA Spec @OneToOne and @ManyToOne are not lazy, but if you set them to be lazy then TopLink will also support this, as long as you enable weaving (weaving is not require for @ToManys). I would recommend you always make your @OneToOne and @ManyToOne lazy. Weaving in TopLink can be enable either through using the TopLink agent when launching your Java VM, or is used automatically in OracleAS or Glassfish, or through using the TopLink static weaving ant task.
In TopLink Essentials lazy on @Basic mappings is not supported, however this will be supported in TopLink 11g.