Java Arrays copyOfRange() Method

Description

The Java Arrays copyOfRange(byte[] original, int from, int to) method copies the specified range of the specified array into a new array.The final index of the range (to), which must be greater than or equal to from, may be greater than original.length, in which case (byte)0 is placed in all elements of the copy whose index is greater than or equal to original.length - from. The length of the returned array will be to - from.

Declaration

Following is the declaration for java.util.Arrays.copyOfRange() method

public static byte[] copyOfRange(byte[] original, int from, int to)

Parameters

  • original − This is the array from which a range is to to be copied.

  • from − This is the initial index of the range to be copied, inclusive.

  • to − This is the final index of the range to be copied, exclusive.

Return Value

This method returns a new array containing the specified range from the original array, truncated or padded with zeros to obtain the required length.

Exception

  • ArrayIndexOutOfBoundsException − If from < 0 or from > original.length()

  • IllegalArgumentException − If if from > to.

  • NullPointerException − If original is null.

Copying an Array of bytes to a Same Sized Array Example

The following example shows the usage of Java Arrays copyOfRange() method. First, we've created an array of bytes. We've printed them. A copy of array with same size is created using copyOfRange() method and printed.

package com.tutorialspoint;

import java.util.Arrays;

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

      byte[] byteArr = { 10, 20, 30, 13 };

      System.out.print("Byte Array: [");
      for (int i = 0; i < byteArr.length; i++) {
         System.out.print(byteArr[i] + " ");
      }

      System.out.print("]\nCopied Array: \n");

      // Create copy of the array of same size
      byte[] byteArrCopy = Arrays.copyOfRange(byteArr, 0, 4);
     
      System.out.print("Byte Array: [");
      for (int i = 0; i < byteArrCopy.length; i++) {
         System.out.print(byteArrCopy[i] + " ");
      }
      System.out.print("]");
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Byte Array: [10 20 30 13 ]
Copied Array: 
Byte Array: [10 20 30 13 ]

Copying an Array of bytes to a Higher Sized Array Example

The following example shows the usage of Java Arrays copyOfRange() method. First, we've created an array of bytes. We've printed them. A copy of array with higher size is created using copyOfRange() method and printed with default values appended.

package com.tutorialspoint;

import java.util.Arrays;

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

      byte[] byteArr = { 10, 20, 30, 13};
      System.out.print("Byte Array: [");
      for (int i = 0; i < byteArr.length; i++) {
         System.out.print(byteArr[i] + " ");
      }
      System.out.print("]\nCopied Arrays: \n");

      // Create copy of the array of greater size
      byte[] byteArrCopy = Arrays.copyOfRange(byteArr, 1, 6);

      System.out.print("Byte Array: [");
      for (int i = 0; i < byteArrCopy.length; i++) {
         System.out.print(byteArrCopy[i] + " ");
      }
      System.out.print("]");
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Byte Array: [10 20 30 13 ]
Copied Arrays: 
Byte Array: [20 30 13 0 0 ]

Copying an Array of bytes to a Lower Sized Array Example

The following example shows the usage of Java Arrays copyOfRange() method. First, we've created an array of bytes. We've printed them. A copy of array with lower size is created using copyOfRange() method and printed.

package com.tutorialspoint;

import java.util.Arrays;

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

      byte[] byteArr = { 10, 20, 30, 13};

      System.out.print("Byte Array: [");
      for (int i = 0; i < byteArr.length; i++) {
         System.out.print(byteArr[i] + " ");
      }
      System.out.print("]\nCopied Arrays: \n");

      // Create copy of the array of lesser size
      byte[] byteArrCopy = Arrays.copyOfRange(byteArr, 1,3);

      System.out.print("Byte Array: [");
      for (int i = 0; i < byteArrCopy.length; i++) {
         System.out.print(byteArrCopy[i] + " ");
      }
      System.out.print("]");
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Byte Array: [10 20 30 13 ]
Copied Arrays: 
Byte Array: [20 30 ]
java_util_arrays.htm
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