Many of the early sewing machines were powered by a treadle mechanism. The treadle was operated by pressing down on it with a foot, or both feet, to cause a rocking movement. This movement spins a large wheel on the treadle frame, connected by a thin leather belt to a smaller driving wheels on the sewing machine.
null. adj. 1. Having no legal force; invalid: render a contract null and void.2.ull. adj. 1. Having no legal force; invalid: render a contract null and void. 2.
class java lang nullpointerexception public class nullpointerexception extends runtimeexception thrown when an application attempts to use null in a case where an object is required these include calling the instance method of a null object accessing or modifying the field of a null objecttaking the length of null as if it were an arrayhrown when an application attempts to use null in a case where an object is required these include calling the instance method of a null object accessing or modifying the field of a null object taking the length of null as if it were an array