Inheritance: If a certain part of multiple classes has the same function, then you can abstract a class and put the same parts of them into the parent class so that they all inherit this class.
Implementation: If the processing goals of multiple classes are the same, but the processing methods are different, then define an interface, which is a standard, and let them implement this interface and each implement their own specific processing. methods to deal with that goal.
The difference between the two:
1. Different modifications
Different modifier modifications; implementation: implements, inheritance: extends;
2 , The number is different
Java only supports multiple inheritance of "interface" and does not support multiple inheritance of "class"; inheritance has a single root in Java, and subclasses can only inherit one parent class.
Summary: single inheritance, multiple implementations.
3. Different attributes
Only global constants (static final) and methods without implementation can be defined in the interface; while in inheritance Attribute methods, variables, constants, etc. can be defined in it.
4. Call different
When an interface is implemented by a class, the abstract method in the interface must be implemented in the class; while inheritance wants If you call that method, call that method.
Summary:
The interface is: a description of the function (method/behavior). The meaning conveyed by the interface is: what can you do if you have a certain function? For example: Serializable represents serializable.
Inheritance is: what is a kind of what, inheritance conveys the meaning: is-a, for example: cat is an animal, and cat is a subclass of animal.
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