ByteBuffer getDouble() method in Java with Examples

getDouble()

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

Syntax:

public abstract double getDouble()

Return Value: This method returns the double value 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 getDouble() method:

Examples 1:

// Java program to demonstrate
// getDouble() 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 double value in the bytebuffer
            bb.asDoubleBuffer()
                .put(1234.3456)
                .put(2884.4444);

            // 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.getDouble() + " ");

            // rewind the Bytebuffer
            bb.rewind();

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

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

            // Reads the  char at this buffer's next position
            // using getDouble() method
            double value1 = bb.getDouble();

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

        catch (BufferUnderflowException e) {

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

Output:

Original ByteBuffer: 
1234.3456 2884.4444 

Byte Value: 1234.3456

Next Byte Value: 2884.4444

Examples 2:

// Java program to demonstrate
// getDouble() 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 double value in the bytebuffer
            bb.asDoubleBuffer()
                .put(1234.3456)
                .put(2884.4444);

            // 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.getDouble() + " ");

            // rewind the Bytebuffer
            bb.rewind();

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

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

            // Reads the  char at this buffer's next position
            // using getDouble() method
            double value1 = bb.getDouble();

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

            // Reads the  char at this buffer's next position
            // using getDouble() method
            double value2 = bb.getDouble();
        }

        catch (BufferUnderflowException e) {
            System.out.println("\nthere are fewer than "
                               + "eight bytes remaining in"
                               + " this buffer");
            System.out.println("Exception Thrown : " + e);
        }
    }
}

Output:

Original ByteBuffer: 
1234.3456 2884.4444 

Byte Value: 1234.3456

Next Byte Value: 2884.4444

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#getDouble–

getDouble(int index)

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

Syntax :

public abstract double getDouble(int index)

Parameters: This method takes index as parameter which is the index from which the Byte will be read.

Return Value: This method returns The double 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 getDouble(int index) method:

Examples 1:

// Java program to demonstrate
// getDouble() 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 double value in the bytebuffer
            bb.asDoubleBuffer()
                .put(1234.3456)
                .put(2884.4444);

            // rewind the Bytebuffer
            bb.rewind();

            // Declaring the variable
            double c;

            // print the ByteBuffer
            System.out.println("Original ByteBuffer: ");
            for (int i = 1; i <= capacity / 8; i++)
                System.out.print(bb.getDouble() + " ");

            // rewind the Bytebuffer
            bb.rewind();

            // Reads the double at this buffer's current position
            // using getDouble() method
            double value = bb.getDouble(0);

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

            // Reads the  char at this buffer's next position
            // using getDouble() method
            double value1 = bb.getDouble(8);

            // print the char 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);
        }
    }
}

Output:

Original ByteBuffer: 
1234.3456 2884.4444 

Byte Value: 1234.3456

Next Byte Value: 2884.4444

Examples 2:

// Java program to demonstrate
// getDouble() 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 double value in the bytebuffer
            bb.asDoubleBuffer()
                .put(1234.3456)
                .put(2884.4444);

            // rewind the Bytebuffer
            bb.rewind();

            // Declaring the variable
            double c;

            // print the ByteBuffer
            System.out.println("Original ByteBuffer: ");
            for (int i = 1; i <= capacity / 8; i++)
                System.out.print(bb.getDouble() + " ");

            // rewind the Bytebuffer
            bb.rewind();

            // Reads the double at this buffer's current position
            // using getDouble() method
            double value = bb.getDouble(0);

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

            // Reads the  char at this buffer's next position
            // using getDouble() method
            double value1 = bb.getDouble(9);

            // print the char 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);
        }
    }
}

Output:

Original ByteBuffer: 
1234.3456 2884.4444 

Byte Value: 1234.3456

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#getDouble-int-