Array setBoolean() Method in Java with Examples

The java.lang.reflect.Array.setBoolean() method is an inbuilt method used to set a specified Boolean value to a specified index of a given object array.

Syntax:

Array.setBoolean(Object []array, int index, boolean value)

Parameter: This method takes three parameters:

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

Return type: This is a void type method and doesn’t returns any value. The update reflects upon the Object array passed as the argument.

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.setBoolean() method:

Program 1:

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

import java.lang.reflect.Array;
public class GfG {
    // main method
    public static void main(String[] args)
    {
        // Declaring and defining boolean array
        boolean b[] = { true, false, true };

        // array before using setBoolean()
        System.out.print("Before Set : ");

        // printing the array
        for (boolean x : b) {
            System.out.print(x + " ");
        }

        // boolean value to be set
        boolean value = true;

        // setBoolean method of class Array
        Array.setBoolean(b, 1, value);

        // array after using setBoolean()
        System.out.print("\nAfter Set : ");

        // printing array
        for (boolean x : b) {
            System.out.print(x + " ");
        }
    }
}
Output:

Before Set : true false true 
After Set : true true true

Program 2: To demonstrate java.lang.NullPointerException

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

import java.lang.reflect.Array;
public class GfG {
    // main method
    public static void main(String[] args)
    {
        // Declaring and defining boolean array to null
        boolean b[] = null;

        try {
            // boolean value to be set
            boolean c = false;

            // passing a null array as parameter
            Array.setBoolean(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 setBoolean()
// method of Array class

import java.lang.reflect.Array;
public class GfG {
    // main method
    public static void main(String[] args)
    {
        // Declaring and defining boolean array
        boolean b[] = { true, false, true };

        try {
            // value to be set
            boolean c = false;

            // passing index as 5 when size is 3
            Array.setBoolean(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 setBoolean()
// method of Array class

import java.lang.reflect.Array;
public class GfG {
    // main method
    public static void main(String[] args)
    {
        // Declaring and defining boolean variable
        boolean b = true;

        try {
            // value to be set
            boolean c = false;

            // passing variable in the place of an array
            Array.setBoolean(b, 5, c);
        }
        catch (Exception e) {
            System.out.println("Exception : " + e);
        }
    }
}
Output:

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