this Keyword in Java

beginner· OOP · Classes & Objects

Problem

The this keyword refers to the current object a constructor or method is running on — it's most often needed when a parameter is deliberately given the same name as the field it initializes.

Write a Student constructor whose parameter is named the same as the field it sets, and use this to tell them apart.

Input

name = "Aditi"

Output

Student name: Aditi

Java Program

Java

class Student {
    String name;

    Student(String name) {
        this.name = name; // this.name is the field; name alone is the parameter
    }
}

public class ThisKeywordDemo {
    public static void main(String[] args) {
        Student student = new Student("Aditi");
        System.out.println("Student name: " + student.name);
    }
}

▶ Run Code

Output

Student name: Aditi

Core Logic

Naming the constructor parameter identically to the field it sets is convenient to read, but requires this.name to specifically mean the field, since plain name would just refer to the parameter.

How It Works

1Student(String name) declares a parameter named name, deliberately matching the field's own name.
2Inside the constructor, name by itself always refers to the parameter — the field is shadowed as long as the parameter is in scope.
3this.name = name; uses this to reach the object's own field specifically, assigning the parameter's value to it.
4Without this., writing just name = name; would assign the parameter to itself and leave the field untouched.

Constructing new Student("Aditi") runs this.name = name;, correctly setting the object's field to "Aditi".

💡

Key Point: this. is only strictly necessary here because the parameter and field share a name — with a differently-named parameter, like studentName, plain assignment would work without it.

Key Concepts

this keywordconstructor parameterfield disambiguation

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super Keyword

toString() Override

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