ByteBuffer get() method in Java with Examples - GeeksforGeeks

24 May, 2019
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);        }    }}
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);        }    }}
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

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);        }    }}
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);        }    }}
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

Vijay Sirra
Java-ByteBuffer
Java-Functions
Java-NIO package
Java
Java
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