What are the necessary conditions for the existence of polymorphism and how to implement it?
- 王林forward
- 2020-08-10 16:40:204376browse
Three necessary conditions for the existence of polymorphism:
(Recommended tutorial: java introductory tutorial)
1. Inheritance
2. Rewriting
3. The parent class reference points to the subclass object (the parent class reference points to the subclass object)
For example:
Parent p = new Child(); List<Integer> myList=new LinkedList<>();
(Learning video recommendation: java course)
Polymorphic implementation method:
Method 1: Rewriting
Method 2: Interface
Method 3: Abstract classes and abstract methods
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