Subroutine mean what (in java)?

The Mechanism that makes possible to transfer control between the calling program and Subroutine is reffered to as SUBROUTINE LINKAGE

marco expand where it invoked ,subroutine will go where the subroutine is defined....

A call to a subroutine. A subroutine is a named/labeled set of commands.

Subroutine is an instruction sequence in a machine or assembly language program that can be prewritten and referred to as often as needed. Subroutine is used for controlling thing e.g. traffic lights burglar alarms they all use subroutine