ByteBuffer arrayOffset() method in Java with Examples
Last Updated :
20 Sep, 2018
The arrayOffset() method of java.nio.ByteBuffer class is used to return the offset within the given buffer’s backing array of the first element of the buffer.
If this buffer is backed by an array then buffer position p corresponds to array index p + arrayOffset().
Invoke the hasArray method before invoking this method in order to ensure that this buffer has an accessible backing array.
Syntax :
public final int arrayOffset()
Return Value: This method returns the offset within this buffer’s array of the first element of the buffer
Exception:: This method throws the ReadOnlyBufferException, If this buffer is backed by an array but is read-only.
Below are the examples to illustrate the arrayOffset() method:
Example 1:
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
int capacity = 4;
try {
ByteBuffer bb = ByteBuffer.allocate(capacity);
bb.put((byte)20);
bb.put((byte)30);
bb.put((byte)40);
bb.put((byte)50);
bb.rewind();
System.out.println("ByteBuffer: "
+ Arrays.toString(bb.array()));
System.out.println("arrayOffset: "
+ bb.arrayOffset());
}
catch (IllegalArgumentException e) {
System.out.println("IllegalArgumentException catched");
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws" + e);
}
}
}
|
Output:
ByteBuffer: [20, 30, 40, 50]
arrayOffset: 0
Example 2:
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
int capacity = 3;
try {
ByteBuffer bb = ByteBuffer.allocate(capacity);
bb.put((byte)20);
bb.put((byte)30);
bb.put((byte)40);
bb.rewind();
ByteBuffer bb1 = bb.asReadOnlyBuffer();
System.out.print("Read only buffer : ");
while (bb1.hasRemaining())
System.out.print(bb1.get() + ", ");
System.out.println("");
System.out.println("\nTry to print the array offset"
+ " of read only buffer");
System.out.println("arrayOffset: " + bb1.arrayOffset());
}
catch (IllegalArgumentException e) {
System.out.println("Exception throws: " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws: " + e);
}
}
}
|
Output:
Read only buffer : 20, 30, 40,
Try to print the array offset of read only buffer
Exception throws: java.nio.ReadOnlyBufferException
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