Arrays.fill(byte[], int, int, byte) in Java

Arrays.fill(byte[], int, int, byte): This method is available in java.util.Arrays class of Java.

Syntax:

void java.util.Arrays.fill(byte[] a, int fromIndex, int toIndex, byte val)

This method takes four arguments one of the type byte arrays, and the other two are of type int and the other one of type byte as its parameters. This method assigns the specified byte value to each element of the specified range of the specified array of bytes.

Parameters: Four parameters are required for this method.

a: the array to be filled.

fromIndex: the index of the first element (inclusive) to be filled with the specified value.

toIndex: the index of the last element (exclusive) to be filled with the specified value.

val: the value to be stored in all elements of the array.

Returns: NA

Throws:

1. IllegalArgumentException - if fromIndex > toIndex.

2. ArrayIndexOutOfBoundsException - if fromIndex < 0 or toIndex > a.length.

Approach 1: When no exceptions

Java

import java.util.Arrays;

public class Arraysfillbyterange {
    public static void main(String[] args) {

        byte a[] = new byte[5];

        byte val = 10;

        int fromIndex = 0, toIndex = 2;
        Arrays.fill(a, fromIndex, toIndex, val);

        System.out.println(Arrays.toString(a));
    }
}

Output:

[10, 10, 0, 0, 0]

Approach 2: IllegalArgumentException 

Java

import java.util.Arrays;

public class Arraysfillbyterange {
    public static void main(String[] args) {

        byte a[] = new byte[5];

        byte val = 10;

        int fromIndex = 3, toIndex = 2;
        Arrays.fill(a, fromIndex, toIndex, val);

        System.out.println(Arrays.toString(a));
    }
}

Output:

Exception in thread "main" java.lang.IllegalArgumentException: fromIndex(3) > toIndex(2)
	at java.base/java.util.Arrays.rangeCheck(Arrays.java:718)
	at java.base/java.util.Arrays.fill(Arrays.java:3307)
	

Approach 3: ArrayIndexOutOfBoundsException 

Java

import java.util.Arrays;

public class Arraysfillbyterange {
    public static void main(String[] args) {

        byte a[] = new byte[5];

        byte val = 10;

        int fromIndex = 0, toIndex = 6;
        Arrays.fill(a, fromIndex, toIndex, val);

        System.out.println(Arrays.toString(a));
    }
}

Output:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 6
	at java.base/java.util.Arrays.rangeCheck(Arrays.java:725)
	at java.base/java.util.Arrays.fill(Arrays.java:3307)