抽象类和抽象方法什么关系？抽象类中可能有抽象方法，也可能没有抽象方法。那位说，就跟没说一样，那抽象类和抽象方法都叫抽象，他们必定有关系，那关系是什么呢？如果一个类中有抽象方法，它必须得是抽象类。

An abstract class may have no abstract method，such as the following class Car. 马  克- t  o --wi n： At this time,the only point and the meaning of abstract class is that we can not instantiated the class, because it is abstract class.Why an abstract class can have a nonabstract method? what is the point? also in logic, think over the following example, car is a bit abstract in that you dont' know exactly whether it is a truck or a jeep or a limersine, 马克-to-win：so it is defined as a abstract class. but no matter whether it is truck,jep, or limersine, it definitely use steering wheel. so its steer() method is an ordinary method instead of an abstract method.  )
Abstract class can’t be instantiated.
例1.7.1---

abstract class Nothing {//里面有方法也照样声明为abstract

void nothing() {
       System.out.println("nothing");
    }
}
abstract class VehMark_to_win {
    abstract void steer();
    abstract void move();
}
class Bike extends VehMark_to_win {//Bike不是抽象的， 所以必须得全部实现abstract方法
    void steer() {
        System.out.println("Turn handlebar");
    }
    void move() {//Bike不是抽象的， 所以必须得实现move方法
        System.out.println("move");
    }
}
abstract class Cart extends VehMark_to_win {
    //因为Cart是抽象的， 可以这里还是什么都不干
}
abstract class Car extends VehMark_to_win {
    void steer() {
        System.out.println("Turn steering wheel");
    }
    void move() {
        System.out.println("move");
    }
}
class Lim extends Car {
    //之所以这里可以什么都不干， 而且还不是抽象的，马克-to-win： 因为父类Car全部实现了Veh的抽象方法
}

更多内容请见原文，原文转载自：https://blog.csdn.net/qq_44639795/article/details/103117449