Java Object-Oriented foundation _final detailed introduction _java

Final:
The drawbacks of inheritance: Breaking the encapsulation of the code, the final appearance just make up for this disadvantage
Final key word:
1-final is a modifier that can modify classes, methods, and variables;
2-final-decorated classes cannot be inherited
3-final modified method can not be overwritten
4-final modified variable is a constant that can only be assigned once and be assigned a value when defined

rules :
The final constants are defined in uppercase letters, and each word is separated by an underscore _.
Example one:
Class father01{
Final String father01_name = "John";
Final int father01_age = 20;

final void Show () {
age=9; Error!!! The age is defined as final, and the definition has been assigned and can no longer be assigned a value
System.out.println ("Name:" + father01_name);
}
}
Final class father02{
}
Class Son01 extends father01{
public void Show () {//Error!!! Methods that are defined by final cannot be overwritten
//
// }
}
Class Son02 extends father02{//error!!! A class that is defined by final cannot be inherited
//
//}