我们可以创建抽象类的对象吗? [英] Can we create an object of abstract class?

问题描述

我只是对抽象类概念感到困惑.请清除我的怀疑. Abstract类的定义表示我们无法创建此类的对象，因此我们称其为A a = new A() { }.示例如下:

I am just confused about abstract class concept. Please clear my doubt. Definition of Abstract class says we can not create object of such class, then what we called like A a = new A() { }. Example is below:

public abstract class AbstractTest {
    public abstract void onClick();
    public void testClick() {

    }
}

public class A {
    AbstractTest test = new AbstractTest() {
        @Override
        public void onClick() {

        }
    };
}

那么test是对象还是什么?

推荐答案

test是AbstractTest的匿名具体子类的对象(请注意，它实现了AbstractTest的所有抽象方法)，这就是为什么可以实例化此子类的原因.

test is an object of an anonymous concrete sub-class of AbstractTest (note that it implements all the abstract methods of AbstractTest), which is why this sub-class can be instantiated.

另一方面，

AbstractTest test = new AbstractTest();

将不会通过编译，因为这将是实例化抽象类的尝试.

wouldn't pass compilation, since that would be an attempt to instantiate an abstract class.

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