A method identifier is always used in association with a remote object reference. A method identifier is defined as follows:

u2 method_id

The method_id is a unique 16-bit hashcode identifier of the remote method within the remote class. This 16-bit hashcode consists of the first two bytes of the SHA-1 message digest function performed on a class specific hash modifier string, followed by the name of the method, followed by the method descriptor representation in UTF-8 format. Representation of a method descriptor is the same as that described in The Java Virtual Machine Specification (Section 4.3.3).