setter method giving an error due to this keyword

Question

The program is throwing an error in the setter method possibly due to the use of this keyword. Why is it giving an error?

The error: Method call setAge(-5), set a field value of "-5" but "0" was expected.expected: <0> but was: <-5>.

public class Person {

    private String firstName;
    private String lastName;
    private int age;

    public String getFirstName(){

        return this.firstName;
    }

    public String getLastName(){

        return this.lastName;
    }

    public int getAge(){

        return this.age;
    }

    public void setFirstName(String firstName){

        this.firstName = firstName;
    }

    public void setLastName(String lastName){

        this.lastName = lastName;
    }

    public void setAge(int age){

        **if(age < 0 || age > 100){
            this.age = 0;** *Why this keyword gives an error here?*
        }
       
        this.age = age;
    }
}

Answer 1

change your set age function to :

public void setAge(int age){

        if(age < 0 || age > 100){
            this.age = 0;
        }
        else
            this.age = age;
       
       
    }

or

public void setAge(int age){

        if(age < 0 || age > 100){
            age = 0;
        }
       
        this.age = age;
    }