ByteBuffer position() methods in Java with Examples

Last Updated : 27 Jun, 2019

The position(int newPosition) method of java.nio.ByteBuffer Class is used to Sets this buffer’s position. If the mark is defined and larger than the new position then it is discarded.

Syntax:

public ByteBuffer position(int newPosition)

Parameters: This method takes the newPosition as parameter which is the new position value. It must be non-negative and no larger than the current limit.

Return Value: This method returns this buffer.

Below are the examples to illustrate the position() method:

Examples 1:

// Java program to demonstrate 
// position() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
        byte[] barr = { 10, 20, 30, 40 }; 
  
        // creating object of ByteBuffer 
        // and allocating size capacity 
        ByteBuffer bb = ByteBuffer.wrap(barr); 
  
        // try to set the position at index 2 
        // using position() method 
        bb.position(2); 
  
        // Set this buffer mark position 
        bb.mark(); 
  
        // try to set the position at index 4 
        // using position() method 
        bb.position(4); 
  
        // display position 
        System.out.println("position before reset: "
                           + bb.position()); 
  
        // try to call reset() to restore 
        // to the position we marked 
        bb.reset(); 
  
        // display position 
        System.out.println("position after reset: "
                           + bb.position()); 
    } 
} 

Output:

position before reset: 4
position after reset: 2

Examples 2:

// Java program to demonstrate 
// position() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
        // creating object of ByteBuffer 
        // and allocating size capacity 
        ByteBuffer bb = ByteBuffer.allocate(4); 
  
        // try to set the position at index 1 
        // using position() method 
        bb.position(1); 
  
        // putting the value of ByteBuffer 
        // using put() method 
        bb.put((byte)10); 
  
        // try to set the position at index 3 
        // using position() method 
        bb.position(3); 
  
        // putting the value of ByteBuffer 
        // using put() method 
        bb.put((byte)30); 
  
        // display position 
        System.out.println("ByteBuffer: "
                           + Arrays.toString(bb.array())); 
    } 
} 

Output:

ByteBuffer: [0, 10, 0, 30]

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

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