Array setDouble() method in Java

The java.lang.reflect.Array.setDouble() is an inbuilt method in Java and is used to set a specified double value to a specified index of a given object array.

Syntax:

Array.setDouble(Object []array, int index, double value)

Parameter: This method takes three parameters:

• array: This is an array of type Object which is to be updated.
• index: This is the index of the array which is to be updated.
• value: This is the double value that is to be set at the given index of the given array.

Exception: This method throws following exceptions:

• NullPointerException– when the array is null.
• IllegalArgumentException– when the given object array is not an Array.
• ArrayIndexOutOfBoundsException– if the given index is not in the range of the size of the array.

Below is the implementation of Array.setDouble() method:

Program 1:

// Java code to demonstrate setDouble()
// method of Array class

import java.lang.reflect.Array;

public class GfG {

    // main method
    public static void main(String[] args)
    {
        // Declaring and defining double array
        double f[] = { 1.0, 2.0, 3.0 };

        // printing the array
        System.out.print("Before Set : ");
        for (double x : f) {
            System.out.print(x + " ");
        }

        double value = 400.0;

        // setDouble method of class Array
        Array.setDouble(f, 1, value);

        // printing array
        System.out.print("\nAfter Set : ");
        for (double x : f) {
            System.out.print(x + " ");
        }
    }
}
Output:

Before Set : 1.0 2.0 3.0 
After Set : 1.0 400.0 3.0

Program 2: To demonstrate java.lang.NullPointerException

// Java code to demonstrate setDouble()
// method of Array class

import java.lang.reflect.Array;

public class GfG {

    // main method
    public static void main(String[] args)
    {
        // Declaring and defining double array to null
        double b[] = null;

        try {
            double c = 1.0;

            // setDouble method of class Array
            // passing null array in parameters
            Array.setDouble(b, 5, c);
        }
        catch (Exception e) {
            System.out.println("Exception : " + e);
        }
    }
}
Output:

Exception : java.lang.NullPointerException

Program 3: To demonstrate java.lang.ArrayIndexOutOfBoundsException

// Java code to demonstrate setDouble()
// method of Array class

import java.lang.reflect.Array;

public class GfG {

    // main method
    public static void main(String[] args)
    {
        // Declaring and defining double array
        double b[] = { 1.0, 2.0, 3.0 };

        try {
            double c = 1.0;

            // setDouble method of class Array
            // passing index 5 when size is 3
            Array.setDouble(b, 5, c);
        }
        catch (Exception e) {
            System.out.println("Exception : " + e);
        }
    }
}
Output:

Exception : java.lang.ArrayIndexOutOfBoundsException

Program 4: To demonstrate java.lang.IllegalArgumentException

// Java code to demonstrate setDouble()
// method of Array class

import java.lang.reflect.Array;

public class GfG {

    // main method
    public static void main(String[] args)
    {
        // Declaring and defining double variable
        double b = 2.0;
        try {
            double c = 1.0;
            // setDouble method of class Array
            // passing a variable as parameter
            // when an array is required instead
            Array.setDouble(b, 5, c);
        }
        catch (Exception e) {
            System.out.println("Exception : " + e);
        }
    }
}
Output:

Exception : java.lang.IllegalArgumentException: Argument is not an array