An annotation that indicates 'lookup' methods, to be overridden by the container
to redirect them back to the
call. This is essentially an annotation-based version of the
attribute, resulting in the same runtime arrangement.
The resolution of the target bean can either be based on the return type
getBean(Class)) or on a suggested bean name (
in both cases passing the method's arguments to the
for applying them as target factory method arguments or constructor arguments.
Such lookup methods can have default (stub) implementations that will simply
get replaced by the container, or they can be declared as abstract - for the
container to fill them in at runtime. In both cases, the container will generate
runtime subclasses of the method's containing class via CGLIB, which is why such
lookup methods can only work on beans that the container instantiates through
regular constructors: i.e. lookup methods cannot get replaced on beans returned
from factory methods where we cannot dynamically provide a subclass for them.
Concrete limitations in typical Spring configuration scenarios:
When used with component scanning or any other mechanism that filters out abstract
beans, provide stub implementations of your lookup methods to be able to declare
them as concrete classes. And please remember that lookup methods won't work on
beans returned from
@Bean methods in configuration classes; you'll have
to resort to
@Inject Provider<TargetBean> or the like instead.