What is the CharBuffer rewind() method in Java?

Note:

The limitLimit of a buffer is its first index that should not be read or written. of the buffer remains unaffected.

Any position previously marked is discarded.

Declaration

The CharBuffer.rewind() method is declared as follows:

buff.rewind()

buff: The CharBuffer to rewind.

Return value

The CharBuffer.rewind() method returns the CharBuffer buff after rewinding.

Code

Consider the code snippet below, which demonstrates the use of the CharBuffer.rewind() method.

import java.nio.*;
import java.util.*;
public class main {
   public static void main(String[] args) {
      int n1 = 4;
      int n2 = 4;
      try {
         CharBuffer buff1 = CharBuffer.allocate(n1);
         buff1.put('a');
         buff1.put('c');
         System.out.println("buff1: " + Arrays.toString(buff1.array()));
         System.out.println("position at(before rewind): " + buff1.position());
         System.out.println("rewind()");
         buff1.rewind();
         System.out.println("position at(after rewind): " + buff1.position());
         buff1.put('d');
         System.out.println("buff1: " + Arrays.toString(buff1.array()));
         
      } catch (IllegalArgumentException e) {
         System.out.println("Error!!! IllegalArgumentException");
      } catch (ReadOnlyBufferException e) {
         System.out.println("Error!!! ReadOnlyBufferException");
      }
   }
}

Explanation

A CharBuffer buff1 is declared in line 8.
Two elements are added to buff1 using the put() method in line 9-10 . After adding the first element, the position of buff1 is incremented from 0 to 1. After adding the second element, the position of buff1 is incremented from 1 to 2.
The position of buff1 before rewind is 2. After calling the rewind() method in line 16, the position of buff1 is set to 0. This is why calling the put() method on buff1 adds the element at the 0th index of buff1.

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