What are the characteristics of abstract classes
Jun 28, 2020 pm 03:35 PMThe 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("我來搽桌子"); } }
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