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Is Java Pass-by-Value or Pass-by-Reference?

3 min readMar 21, 2025

If you’re confused whether Java is pass-by-value or pass-by-reference, you’re not alone. This is one of the most misunderstood topics in Java, especially among beginners and even experienced developers preparing for interviews.

Let’s simplify the answer with examples. ✅

✅ Quick Answer:

Java is always pass-by-value.
Yes — even when you pass objects.

But… it behaves a bit differently when you pass objects compared to primitive types, which causes the confusion.

Let’s explore both.

🔹 What is Pass-by-Value?

Pass-by-value means a copy of the variable is passed to the method. Changes made to the copy do not affect the original.

🔸 What is Pass-by-Reference?

Pass-by-reference means the reference (memory address) itself is passed. So any changes affect the original object or variable.

🚀 Java Pass-by-Value: Explained

In Java, when you pass a variable to a method, Java creates a copy of that variable’s value and passes it.

This is true for:

Primitive types → copy of the value
Objects → copy of the reference

Let’s see both with examples 👇

1️⃣ Example with Primitive Type (int, boolean, etc.)

public class Test {
    public static void modify(int x) {
        x = 100;
    }

    public static void main(String[] args) {
        int num = 50;
        modify(num);
        System.out.println(num);  // Output: 50 ❌ Not changed
    }
}

🔍 Explanation:
A copy of num is passed to the modify() method. The original num remains unchanged.

2️⃣ Example with Objects

class Student {
    String name;
}

public class Test {
    public static void update(Student s) {
        s.name = "Priya";  // modifying internal field
    }

    public static void main(String[] args) {
        Student s1 = new Student();
        s1.name = "Amit";

        update(s1);
        System.out.println(s1.name);  // Output: Priya ✅ Changed
    }
}