BioJava throws exceptions when methods are invoked with invalid parameters.

Only static methods can be invoked without a reference to an object.

This means that the method is invoked using a specific instance of the class.

This method must be invoked for each header that needs to be sent with the request.

To detect states 1 and 2, the listener must be defined before the open method is invoked.

The open method must be invoked before the send method is invoked.

At a more sophisticated level, computerised methods of a technique known as discriminant analysis can be invoked.

If the object Servant exists on the same server where the method is invoked, they also mediate the local calls.

When an object receives a message, a method matching the message name is invoked.

This method is invoked only when the servlet is first loaded into memory.