Find the difference between final and effectively final as below:

Final:- Any variable that cannot be modified once it is initialized can be final variable. You cannot modified again that variable.

Ex:  final int var=20;

in the above example you can't modified the variable(var=20) because you put the final keyword in front of that.

Effectively Final:- Any variable that can be defined outside the Lamda Expression and Initialized only once inside the scope(in method or a class) can be called effectively final . It is used with Lamda Expression but you do not need to put final keyword in front of that variable .

import java.util.ArrayList;
import java.util.List;

public class EffectiveFinal {

    public static void main(String[] args) {


        List>String> listStrings = new ArrayList>String>();
        listStrings.add("Salman");
        listStrings.add("Shahrukh");


        String Lastname = "Khan";

            listStrings.stream().forEach(str -> System.out.println("Lambda Expression: " + str + " " + Lastname));
      }
}