# ByteBuffer compact() method in Java

Java 8Object Oriented ProgrammingProgramming

The buffer can be compacted using the compact() method in the class java.nio.ByteBuffer. This method does not require a parameter and it returns the new compacted ByteBuffer with the same content as the original buffer. If the buffer is read-only, then the ReadOnlyBufferException is thrown.

A program that demonstrates this is given as follows −

## Example

Live Demo

import java.nio.*;
import java.util.*;
public class Demo {
public static void main(String[] args) {
int n = 5;
try {
ByteBuffer buffer = ByteBuffer.allocate(n);
buffer.put((byte)5);
buffer.put((byte)8);
buffer.put((byte)3);
System.out.println("The Original ByteBuffer is: " + Arrays.toString(buffer.array()));
System.out.println("The position is: " + buffer.position());
System.out.println("The limit is: " + buffer.limit());
ByteBuffer bufferCompact = buffer.compact();
System.out.println("\nThe Compacted ByteBuffer is: " + Arrays.toString(bufferCompact.array()));
System.out.println("The position is: " + bufferCompact.position());
System.out.println("The limit is: " + bufferCompact.limit());
} catch (IllegalArgumentException e) {
System.out.println("Error!!! IllegalArgumentException");
}
}
}

## Output

The Original ByteBuffer is: [5, 8, 3, 0, 0]
The position is: 3
The limit is: 5
The Compacted ByteBuffer is: [0, 0, 3, 0, 0]
The position is: 2
The limit is: 5
Published on 04-Mar-2019 07:41:10