Java's final keyword

Final keyword (can be read, not writable, read-only)

1. The value of the final variable cannot be changed

①, final member variable

②, final local variable (formal parameter)//meaning "argument" is not allowed to change once it is passed into my method

2. Final method can not be rewritten

3. Final class can not be inherited

Is there a final class in the Java API? A: Yes, such as the String class. The API is declared as: Public final class string{};

 Public classtestfinal{ Public Static voidMain (String args[]) {T T=NewT (); //t.i=2; //cannot assign a value to the final variable i                    }}classt{Final intI =1;}classtt{ Public Final voidoverRide () {}}classTTTextendstt{/*Public final void override () {//appears: Override () in TTT cannot overwrite override ()} in TT*/}Final classtttt{}/*class TTTTT extends tttt{//will appear: cannot inherit from the final class TTTT}*/

Java's final keyword