The PostConstruct annotation is used on a method that needs to be executed after dependency injection is done to perform any initialization.

  The PostConstruct annotation is used on a method that needs to be executed
after dependency injection is done to perform any initialization. This
method MUST be invoked before the class is put into service. This
annotation MUST be supported on all classes that support dependency
injection. The method annotated with PostConstruct MUST be invoked even
if the class does not request any resources to be injected. Only one
method can be annotated with this annotation. The method on which the
PostConstruct annotation is applied MUST fulfill all of the following
criteria -
- The method MUST NOT have any parameters except in the case of EJB
interceptors in which case it takes an InvocationC ontext object as
defined by the EJB specification.
- The return type of the method MUST be void.
- The method MUST NOT throw a checked exception.
- The method on which PostConstruct is applied MAY be public, protected,
package private or private.
- The method MUST NOT be static except for the application client.
- The method MAY be final.
- If the method throws an unchecked exception the class MUST NOT be put into
service except in the case of EJBs where the EJB can handle exceptions and
even recover from them.