FloatBuffer mark() methods in Java with Examples

Last Updated : 10 Sep, 2019
The mark() method of java.nio.FloatBuffer Class is used to mark the current position of this FloatBuffer as the mark of this buffer. Syntax: 
public final FloatBuffer mark()
Parameters: The method does not take any parameters. Return Value: This method returns this FloatBuffer after setting the buffer's mark at the current position. Below examples illustrate the mark() method: Examples 1: Java 
// Java program to demonstrate
// mark() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        try {

            float[] farr = { 10.5f, 20.5f, 30.5f, 40.5f };

            // creating object of FloatBuffer
            // and allocating size capacity
            FloatBuffer fb = FloatBuffer.wrap(farr);

            // try to set the position at index 2
            fb.position(2);

            // Set this buffer mark position
            // using mark() method
            fb.mark();

            // try to set the position at index 4
            fb.position(4);

            // display position
            System.out.println("position before reset: "
                               + fb.position());

            // try to call reset() to restore
            // to the position we marked
            fb.reset();

            // display position
            System.out.println("position after reset: "
                               + fb.position());
        }

        catch (InvalidMarkException e) {
            System.out.println("New position "
                               + "is less than "
                               + "the position "
                               + "marked before ");
            System.out.println("Exception throws: "
                               + e);
        }
    }
}
Output: 
position before reset: 4
position after reset: 2
Examples 2: To demonstrate InvalidMarkException Java 
// Java program to demonstrate
// mark() method

import java.nio.*;
import java.util.*;

public class GFG {

    public static void main(String[] args)
    {

        try {

            float[] farr = { 10.5f, 20.5f, 30.5f, 40.5f };

            // creating object of FloatBuffer
            // and allocating size capacity
            FloatBuffer fb = FloatBuffer.wrap(farr);

            // try to set the position at index 2
            fb.position(2);

            // Set this buffer mark position
            // using mark() method
            fb.mark();

            // try to set the position at index 1
            fb.position(1);

            // display position
            System.out.println("position before reset: "
                               + fb.position());

            // try to call reset() to restore
            // to the position we marked
            fb.reset();

            // display position
            System.out.println("position after reset: "
                               + fb.position());
        }

        catch (InvalidMarkException e) {
            System.out.println("\nNew position "
                               + "is less than "
                               + "the position "
                               + "marked before ");
            System.out.println("Exception throws: "
                               + e);
        }
    }
}
Output: 
position before reset: 1

New position is less than the position marked before 
Exception throws: java.nio.InvalidMarkException
Reference: https://docs.oracle.com/javase/9/docs/api/java/nio/FloatBuffer.html#mark--
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