OptionalDouble equals() method in Java with examples

OptionalDouble help us to create an object which may or may not contain a Double value. The equals(Object obj) method help us to compare this OptionalDouble object with the passed object as a parameter and it returns true if objects are equal.

The other object is considered equal to this OptionalDouble if:

• it is also an OptionalDouble and;
• both instances have no value present or;
• the present values are “equal to” each other via ==.

Syntax:

public boolean equals(Object obj)

Parameters: This method accepts an obj which is an object to be tested for equality.

Return value: This method returns true if the other object is “equal to” this object otherwise false.

Below programs illustrate equals(Object obj) method:

Program 1:

// Java program to demonstrate
// OptionalDouble.equals(Object obj) method

import java.util.OptionalDouble;

public class GFG {

    public static void main(String[] args)
    {

        // Create first OptionalDouble object
        OptionalDouble opDouble1
            = OptionalDouble.of(452.13246);

        System.out.println("OptionalDouble 1: "
                           + opDouble1.toString());

        // Create second OptionalDouble object
        OptionalDouble opDouble2
            = OptionalDouble.of(452.13246);

        System.out.println("OptionalDouble 2: "
                           + opDouble2.toString());

        // Check if these two objects are equal
        // using equals(Object obj)
        System.out.println("Are both objects equal: "
                           + opDouble1.equals(opDouble2));
    }
}

Output:

OptionalDouble 1: OptionalDouble[452.13246]
OptionalDouble 2: OptionalDouble[452.13246]
Are both objects equal: true

Program 2:

// Java program to demonstrate
// OptionalDouble.equals(Object obj) method

import java.util.OptionalDouble;

public class GFG {

    public static void main(String[] args)
    {
        // Create first OptionalDouble object
        OptionalDouble opDouble1
            = OptionalDouble.of(3179464.92);

        System.out.println("OptionalDouble 1: "
                           + opDouble1.toString());

        // Create second OptionalDouble object
        OptionalDouble opDouble2
            = OptionalDouble.of(4521.3246);

        System.out.println("OptionalDouble 2: "
                           + opDouble2.toString());

        // Check if these two objects are equal
        // using equals(Object obj)
        System.out.println("Are both objects equal: "
                           + opDouble1.equals(opDouble2));
    }
}

Output:

OptionalDouble 1: OptionalDouble[3179464.92]
OptionalDouble 2: OptionalDouble[4521.3246]
Are both objects equal: false

References: https://docs.oracle.com/javase/10/docs/api/java/util/OptionalDouble.html#equals?(Object obj)