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[英]Does a class which is extending an abstract class still has to implement the interface that abstract class is implementing?: java
[英]how to reference a class which is extending a class and implementing an interface
我有一个扩展了另一个类并实现一个接口的类,所以现在该类的引用类型是什么。到现在ClasscastException
如果我试图将基本类型转换为子类型,则会得到ClasscastException
。
例如
public class Child extends Parent implements SomeInterface
{
}
SomeInterface childObject = new Child();
childObject2 = (Child)childObject;
要么
Parent p = new Child();
childObject2 = (Child)p;
在这两种情况下,我都会遇到class cast exception
您不能将子类的对象强制转换为超类。因为超类具有一般性,而子类具有特殊性。
SuperClass sup = (SuperClass) new SubClass();
SubClass sub1 = (SubClass) sup;
您可以参考: 将超类转换为子类
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