The characteristics of abstract classes are: 1. Both abstract classes and abstract methods need to be modified with abstract; 2. There can be no abstract methods in abstract classes, but abstract methods must be in abstract classes; 3. Abstract classes cannot directly Create objects; 4. Abstract classes have construction methods.
Characteristics of abstract classes:
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1 , both abstract classes and abstract methods need to be modified with abstract;
2. Abstract methods must be in abstract classes, and there can be no abstract methods in abstract classes;
3. Abstract classes cannot directly create objects. (Instantiation);
4. If a subclass of an abstract class overrides all abstract methods, it will be a concrete class;
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5. If the subclass of an abstract class does not override all abstract methods, then the subclass is still an abstract class;
6. The abstract class has a construction method, which is intended to allow the subclass to To call the constructor initialization;
Code example:
abstract class Emoplyee {
String name;
public Emoplyee(String name) {
this.name = name;
}
public void test() {
}
public abstract void work();
// public abstract void sleep();
}
class Waiter extends Emoplyee {
public Waiter(String s) {
super(s);
}
public void work() {
System.out.println("我来搽桌子");
}
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