OOD core concepts
1.Encapsulation
2.Inheritence:子类只能继承父类部分的方法和对象。
3.Polyphosim:父类引用可以持有子类对象,只能调用父类的方法,不能调用特有方法。多态的实现:1.继承,多个子类重写2.接口,多种实现。
Difference between Abstract class && Interface
1.single extends&&multi implementation
2.Abstract can have unabstract methods,interface can only have abstract methods. interface assumes methods:public static final.