What is the FloatBuffer mark() method in Java?

FloatBuffer is a built-in class available in the java.nio.FloatBuffer package.

FloatBuffer implements a float-point buffer and allows the user to perform various categories of operations upon buffers of datatype float.

mark() is a method defined in the FloatBuffer class. The following is the function prototype:

public final FloatBuffer mark()

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

class Edpresso {
    public static void main( String args[] ) {
        
        // Creating a Floatbuffer
        FloatBuffer buff = FloatBuffer.allocate(5);
        
        // Populating FloatBuffer
        buff.put(3.14F);
        buff.put(7.86F);
        buff.put(4.67F);
        buff.put(11.33F);
        buff.put(63.03F);

        // Print buffer
        System.out.println(Arrays.toString(buff.array()));

        // Jump to 3rd index of buffer
        buff.position(3);
        System.out.println("Current position is: " + buff.position());

        // Mark current position
        buff.mark();
        System.out.println("Marked position: " + buff.position());

        // Jump to 5th index of buffer
        buff.position(5);
        System.out.println("Current position is: " + buff.position());

        // Invoking reset()
        buff.reset();

        // Print position after reset
        System.out.println("Position after reset is: " + buff.position()); 

        // Jumping to a position behind the mark
        buff.position(1);
        System.out.println("Current position is: " + buff.position());

        // Invoke reset()
        buff.reset();





    }
}

In the above example, we create a FloatBuffer and populate it with random float values.

We jump to the 3rd index of the buffer and invoke the mark() method. As shown in the output, the position is successfully marked.

Next, we jump to the 5th index of the buffer and call reset(). As the 3rd index was already marked, calling reset() brings the current position back to the mark.

Then, we jump to the 1st index. This position is behind the mark which is set at the 3rd index.

Invoking reset() now throws an InvalidMarkException as our current position (1) is less than the mark (3).

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What is the FloatBuffer mark() method in Java?

Functionality

Parameters and return value

Code