setter method giving an error due to this keyword-CodePudding

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;
    }
}

CodePudding user response：

change your set age function to :

public void setAge(int age){

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

public void setAge(int age){

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

CodePudding user response：

Use Instead

public String getFirstName(){

    return firstName;
}