What is reference variable in Java?

The only way you can access an object is through a reference variable. A reference variable is declared to be of a specific type and that type can never be changed. Reference variables can be declared as static variables, instance variables, method parameters, or local variables.

A reference variable that is declared as final can’t never be reassigned to refer to a different object. The data within the object can be modified, but the reference variable cannot be changed.

package org.kodejava.example.basic;

public class ReferenceDemo {
    public static void main(String[] args) {
        // Declaration of Reference variable
        Reference ref1, ref2;

        // ref3 is declared final, ref3 can't be reassigned
        // or refer to different object
        final Reference ref3;

        // assign ref1 with object Reference
        ref1 = new Reference("This is the first reference variable", 1);

        // access method getNumber() of object Reference through
        // variable ref1
        int number = ref1.getNumber();
        System.out.println("number= " + number);

        // assign ref2 with object Reference
        ref2 = new Reference("This is the second reference variable", 2);

        // passing ref2 as method parameter of printText() method
        ReferenceDemo.printText(ref2);

        // assign ref3 with object Reference
        ref3 = new Reference("This is the third reference variable", 3);

        // try to reassign ref3 will cause a compile-time error
        // ref3 = new Reference("Try to reassign", 3);

    }

    public static void printText(Reference reference) {
        String text = reference.getText();
        System.out.println(text);
    }
}
package org.kodejava.example.basic;

public class Reference {
    private int number;
    private String text;

    Reference(String text, int number) {
        this.text = text;
        this.number = number;
    }

    public String getText() {
        return text;
    }

    public int getNumber() {
        return number;
    }
}
Wayan Saryada

Wayan Saryada

A programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, JPA, etc. If you need help on Java programming you can hire me on Fiverr.
Wayan Saryada

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