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-

ByteBuffer getDouble() method in Java with Examples

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