ByteBuffer get() method in Java with Examples

get()

The get() method of java.nio.ByteBuffer class is used to read the byte at the buffer’s current position, and then increments the position.

Syntax :

public abstract byte get()

Return Value: This method returns the byte at the buffer’s current position.

Throws: This method throws BufferUnderflowException – If the buffer’s current position is not smaller than its limit, then this exception is thrown.

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

Examples 1:

// Java program to demonstrate
// get() method

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

public class GFG {

    public static void main(String[] args)
    {

        // Declaring the capacity of the ByteBuffer
        int capacity = 5;

        // Creating the ByteBuffer
        try {

            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);

            // putting the int to byte value in ByteBuffer
            bb.put((byte)20);
            bb.put((byte)30);
            bb.put((byte)40);
            bb.rewind();

            // print the ByteBuffer
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array()));

            // Reads the byte at this buffer's current position
            // using get() method
            byte value = bb.get();

            // print the byte value
            System.out.println("\nByte Value: " + value);

            // Reads the  Byte at this buffer's next position
            // using get() method
            byte value1 = bb.get();

            // print the Float value
            System.out.print("\nNext Byte Value: " + value1);
        }

        catch (IllegalArgumentException e) {

            System.out.println("\nException Thrown : " + e);
        }

        catch (ReadOnlyBufferException e) {

            System.out.println("\nException Thrown : " + e);
        }

        catch (BufferUnderflowException e) {

            System.out.println("\nException Thrown : " + e);
        }
    }
}

Output:

Original ByteBuffer:  [20, 30, 40, 0, 0]

Byte Value: 20

Next Byte Value: 30

Examples 2:

// Java program to demonstrate
// get() method

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

public class GFG {

    public static void main(String[] args)
    {

        // Declaring the capacity of the ByteBuffer
        int capacity = 3;

        // Creating the ByteBuffer
        try {

            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);

            // putting the int to byte typecast value in ByteBuffer
            bb.put((byte)20);
            bb.put((byte)30);

            // print the ByteBuffer
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array()));

            // Reads the byte at this buffer's current position
            // using get() method
            byte value = bb.get();

            // print the byte value
            System.out.println("\nByte Value: " + value);

            // Reads the Byte at this buffer's next position
            // using get() method
            System.out.print("\nsince the buffer current position is incremented");
            System.out.print(" to greater than its limit ");

            byte value1 = bb.get();

            // print the Byte value
            System.out.print("\nNext Byte Value: " + value1);
        }

        catch (IllegalArgumentException e) {

            System.out.println("\nIllegalArgumentException catched");
        }

        catch (ReadOnlyBufferException e) {

            System.out.println("\nReadOnlyBufferException catched");
        }

        catch (BufferUnderflowException e) {

            System.out.println("\nException throws : " + e);
        }
    }
}

Output:

Original ByteBuffer:  [20, 30, 0]

Byte Value: 0

since the buffer current position is incremented to greater than its limit 
Exception throws : java.nio.BufferUnderflowException

get(int index)

The get(int index) method of ByteBuffer is used to read the article at a specified index.

Syntax :

public abstract byte get(int index)

Parameters: This method takes index (The index from which the Byte will be read) as a parameter.

Return Value: This method returns the Byte value at the given index.

Exception: This method throws IndexOutOfBoundsException. If index is negative or not smaller than the buffer’s limit this exception is thrown.

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

Examples 1:

// Java program to demonstrate
// get(int index) method

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

public class GFG {

    public static void main(String[] args)
    {

        // Declaring the capacity of the ByteBuffer
        int capacity = 3;

        // Creating the ByteBuffer
        try {

            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);

            // putting the int to byte typecast value in ByteBuffer
            bb.put((byte)20);
            bb.put((byte)30);
            bb.put((byte)40);

            // print the ByteBuffer
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array()));

            // Reads the Byte at the index 0 of the Bytebuffer
            // using get() method
            byte value0 = bb.get(0);

            // print the Byte value
            System.out.println("\nByte Value at index 0: " + value0);

            // Reads the Byte at the index 1 of the Bytebuffer
            // using get() method
            byte value1 = bb.get(1);

            // print the Byte value
            System.out.println("\nByte Value at index 1: " + value1);

            // Reads the Byte at the index 2 of the Bytebuffer
            // using get() method
            byte value2 = bb.get(2);

            // print the Byte value
            System.out.println("\nByte Value at index 2: " + value2);
        }

        catch (IllegalArgumentException e) {

            System.out.println("\nIllegalArgumentException catched");
        }

        catch (IndexOutOfBoundsException e) {

            System.out.println("\nReadOnlyBufferException catched");
        }

        catch (BufferUnderflowException e) {

            System.out.println("\nException throws : " + e);
        }
    }
}

Output:

Original ByteBuffer:  [20, 30, 40]

Byte Value at index 0: 20

Byte Value at index 1: 30

Byte Value at index 2: 40

Examples 2:

// Java program to demonstrate
// get(int index) method

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

public class GFG {

    public static void main(String[] args)
    {

        // Declaring the capacity of the ByteBuffer
        int capacity = 3;

        // Creating the ByteBuffer
        try {

            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);

            // putting the int to byte typecast value in ByteBuffer
            bb.put((byte)20);
            bb.put((byte)30);
            bb.put((byte)40);

            // print the ByteBuffer
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array()));

            // Reads the Byte at the index 0 of the Bytebuffer
            // using get() method
            byte value0 = bb.get(0);

            // print the Byte value
            System.out.println("\nByte Value at index 0: " + value0);

            // Reads the Byte at the index 1 of the Bytebuffer
            // using get() method
            byte value1 = bb.get(1);

            // print the Byte value
            System.out.println("\nByte Value at index 1: " + value1);

            // Reads the Byte at the index 4 of the Bytebuffer
            // using get() method
            System.out.println("\nTrying to get the byte"
                               + " of index greater than its limit ");
            byte value2 = bb.get(4);

            // print the Byte value
            System.out.println("\nByte Value at index 4: " + value2);
        }

        catch (IndexOutOfBoundsException e) {

            System.out.println("\nException throws : " + e);
        }

        catch (BufferUnderflowException e) {

            System.out.println("\nException throws : " + e);
        }
    }
}

Output:

Original ByteBuffer:  [20, 30, 40]

Byte Value at index 0: 20

Byte Value at index 1: 30

Trying to get the byte of index greater than its limit 

Exception throws : java.lang.IndexOutOfBoundsException