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.
It is simple, put a null check! Surround your object with if statement like. Object mayBeNullObj = getTheObjectItMayReturnNull(); if (mayBeNullObj != null) { // to avoid NullPointerException. mayBeNullObj.workOnIt(); }. If you think it is so easy and the subject is done, then you are caught wrong.ava API documentation says that NullPointerException can be thrown, when there is an attempt to use null where an object is required. That is you are trying to access a reference where there is no value.