EJB 3.1 FR 18.2.5.3:
A timeout callback method must have one of the two signatures below, where <METHOD> designates the method name[101].

void <METHOD>()

void <METHOD>(Timer timer)[102]

[101] If the bean implements the TimedObject interface, the Timeout annotation may optionally be applied to the ejbTimeout method.

[102] An earlier version of the specification required that timeout callbacks accept the Timer parameter but did not require that this parameter be listed when declared via .xml. To preserve backward compatibility, a <timeout-method> that does not include a <method-param> element for the javax.ejb.Timer parameter may be used to match either a timeout method signtaure with or without a Timer parameter. If a timer methods are overloaded, a <timeout-method> with an empty <method-params> element may be used to explicitly refer to a the no-arg timout method.