ByteBuffer getLong() method in Java with Examples

getLong()

The getLong() method of java.nio.ByteBuffer class is used to read the next eight bytes at this buffer’s current position, composing them into a long value according to the current byte order, and then increments the position by eight.

Syntax:

public abstract long getLong()

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

Throws: This method throws BufferUnderflowException – If there are fewer than four bytes remaining in this buffer.

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

Examples 1:

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// Java program to demonstrate
// getLong() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the ByteBuffer
        int capacity = 16;
  
        // Creating the ByteBuffer
        try {
  
            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
  
            // putting the long value in the bytebuffer
            bb.asLongBuffer()
                .put(1233003)
                .put(2292292);
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // print the ByteBuffer
            System.out.println("Original ByteBuffer: ");
            for (int i = 1; i <= capacity / 8; i++)
                System.out.print(bb.getLong() + " ");
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // Reads the long at this buffer's current position
            // using getLong() method
            long value = bb.getLong();
  
            // print the long value
            System.out.println("\n\nByte Value: " + value);
  
            // Reads the  long at this buffer's next position
            // using getLong() method
            long value1 = bb.getLong();
  
            // print the long value
            System.out.print("\nNext Byte Value: " + value1);
        }
  
        catch (BufferUnderflowException e) {
  
            System.out.println("\nException Thrown : " + e);
        }
    }
}

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Output:

Original ByteBuffer: 
1233003 2292292 

Byte Value: 1233003

Next Byte Value: 2292292

Examples 2:

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// Java program to demonstrate
// getLong() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the ByteBuffer
        int capacity = 16;
  
        // Creating the ByteBuffer
        try {
  
            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
  
            // putting the long value in the bytebuffer
            bb.asLongBuffer()
                .put(1233003)
                .put(2292292);
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // print the ByteBuffer
            System.out.println("Original ByteBuffer: ");
            for (int i = 1; i <= capacity / 8; i++)
                System.out.print(bb.getLong() + " ");
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // Reads the long at this buffer's current position
            // using getLong() method
            long value = bb.getLong();
  
            // print the long value
            System.out.println("\n\nByte Value: " + value);
  
            // Reads the  long at this buffer's next position
            // using getLong() method
            long value1 = bb.getLong();
  
            // print the long value
            System.out.print("\nNext Byte Value: " + value1);
  
            // Reads the  long at this buffer's next position
            // using getLong() method
            long value2 = bb.getLong();
        }
  
        catch (BufferUnderflowException e) {
            System.out.println("\nthere are fewer than "
                               + "eight bytes remaining in this buffer");
            System.out.println("Exception Thrown : " + e);
        }
    }
}

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Output:

Original ByteBuffer: 
1233003 2292292 

Byte Value: 1233003

Next Byte Value: 2292292
there are fewer than eight bytes remaining in this buffer
Exception Thrown : java.nio.BufferUnderflowException

Reference: https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getLong–

getLong(int index)

The getLong(int index) method of ByteBuffer is used to read four bytes at the given index, composing them into a float value according to the current byte order.

Syntax:

public abstract long getLong(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 long 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 getLong(int index) method:

Examples 1:

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// Java program to demonstrate
// getLong() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the ByteBuffer
        int capacity = 16;
  
        // Creating the ByteBuffer
        try {
  
            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
  
            // putting the long value in the bytebuffer
            bb.asLongBuffer()
                .put(1233003)
                .put(2292292);
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // print the ByteBuffer
            System.out.println("Original ByteBuffer: ");
            for (int i = 1; i <= capacity / 8; i++)
                System.out.print(bb.getLong() + " ");
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // Reads the long at this buffer's current position
            // using getLong() method
            long value = bb.getLong(0);
  
            // print the long value
            System.out.println("\n\nByte Value: " + value);
  
            // Reads the  long at this buffer's next position
            // using getLong() method
            long value1 = bb.getLong(8);
  
            // print the long value
            System.out.print("\nNext Byte Value: " + value1);
        }
  
        catch (IndexOutOfBoundsException e) {
  
            System.out.println("\nindex is negative or "
                               + "smaller than the buffer's limit, "
                               + "minus seven");
            System.out.println("Exception Thrown : " + e);
        }
    }
}

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Output:

Original ByteBuffer: 
1233003 2292292 

Byte Value: 1233003

Next Byte Value: 2292292

Examples 2:

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code

// Java program to demonstrate
// getLong() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the ByteBuffer
        int capacity = 16;
  
        // Creating the ByteBuffer
        try {
  
            // creating object of ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
  
            // putting the long value in the bytebuffer
            bb.asLongBuffer()
                .put(1233003)
                .put(2292292);
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // print the ByteBuffer
            System.out.println("Original ByteBuffer: ");
            for (int i = 1; i <= capacity / 8; i++)
                System.out.print(bb.getLong() + " ");
  
            // rewind the Bytebuffer
            bb.rewind();
  
            // Reads the long at this buffer's current position
            // using getLong() method
            long value = bb.getLong(0);
  
            // print the long value
            System.out.println("\n\nByte Value: " + value);
  
            // Reads the  long at this buffer's next position
            // using getLong() method
            long value1 = bb.getLong(11);
  
            // print the long value
            System.out.print("\nNext Byte Value: " + value1);
        }
  
        catch (IndexOutOfBoundsException e) {
  
            System.out.println("\nindex is negative or"
                               + " smaller than the buffer's limit, "
                               + "minus seven");
            System.out.println("Exception Thrown : " + e);
        }
    }
}

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Output:

Original ByteBuffer: 
1233003 2292292 

Byte Value: 1233003

index is negative or smaller than the buffer's limit, minus seven
Exception Thrown : java.lang.IndexOutOfBoundsException

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



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