CharBuffer charAt() methods in Java with Examples

Last Updated : 23 Jul, 2019

The charAt() method of java.nio.CharBuffer Class is used to read the character at the given index relative to the current position.

Syntax:

public final char charAt(int index)

Parameters: This method takes the index of the character to be read, relative to the position; must be non-negative and smaller than remaining().

Return Value: This method returns the character at index position() + index.

Exception: This method throws IndexOutOfBoundsException if the preconditions on index do not hold.

Below are the examples to illustrate the charAt(int index) method:

Example 1:

   // Java program to demonstrate 
// charAt() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(3); 
  
            // append the value in CharBuffer 
            // using append() method 
            charbuffer.append('a') 
                .append('b') 
                .append('c') 
                .rewind(); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
  
            // Read char at particular Index 
            // using charAt() method 
            char value = charbuffer.charAt(2); 
  
            // Display the value 
            System.out.println("\nvalue at Index 0 is : "
                               + value); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
  
            System.out.println("\nindex is greater than"
                               + " the capacity minus 1"); 
            System.out.println("Exception throws : " + e); 
        } 
    } 
} 
 
  

Output:

  Original CharBuffer:  [a, b, c]    value at Index 0 is : c

Example 2: To demonstrate IndexOutOfBoundsException.

   // Java program to demonstrate 
// charAt() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(3); 
  
            // append the value in CharBuffer 
            // using append() method 
            charbuffer.append('a') 
                .append('b') 
                .append('c') 
                .rewind(); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
  
            // Read char at particular Index 
            // using charAt() method 
            char value = charbuffer.charAt(3); 
  
            // Display the value 
            System.out.println("\nvalue at Index 0 is : "
                               + value); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
  
            System.out.println("\nindex is greater than"
                               + " the capacity minus 1"); 
            System.out.println("Exception throws : " + e); 
        } 
    } 
} 
 
  

Output:

  Original CharBuffer:  [a, b, c]    index is greater than the capacity minus 1  Exception throws : java.lang.IndexOutOfBoundsException

Reference: https://docs.oracle.com/javase/9/docs/api/java/nio/CharBuffer.html#charAt-int-

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CharBuffer charAt() methods in Java with Examples

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