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How to clean a buffer using clear method in java.

In this tutorial you will see how to clean a buffer using clear method in java.

How to clean a buffer using clear method in java.

                In this tutorial, we will discuss the use of clear() method. The Buffer class is a 
container for handling primitive data type. The clear() method is available in Buffer class.
The ByteBuffer class is available in java.nio package. 

               In this example, the clear() method clean a buffer for further use, and after clear
 method the position will be zero and limit will be capacity of buffer. The method allocate
( int capacity) creates a new byte buffer. The FileChannel class creates a channel for reading,
and writing file. The FileChannel is similar to the stream but they are few different. The channel 
can read write both, but stream can either read-only or write-only. The getChannel method of
FileInputStream class returns the channel associated with this file input stream. The read()  
method of FileChannel class fills byte buffer.

About ByteBuffer API:

The java.nio.ByteBuffer class extends java.nio.Buffer class. It provides the following methods:

Return type Method Description
static ByteBuffer allocate( int capacity)  The allocate() method create a byte buffer of specified capacity. 


import java.nio.*;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

public class ByteBufferClear {
public static void main(String[] argsthrows IOException {
FileInputStream aFile = new FileInputStream("bharat.txt");
 FileInputStream bFile = new FileInputStream("test.txt");
    FileChannel inChannel = aFile.getChannel();
    FileChannel inChannelb = bFile.getChannel();
    ByteBuffer buf = ByteBuffer.allocate(55);
    int bytesRead =;
System.out.print("\nBefore clear method data in buffer\n");
    while (buf.hasRemaining()) {
    int bytesReadb =;
System.out.print("\nAfter clear method data in buffer\n");
    while (buf.hasRemaining()) {

Following is the output if you run the application:

C:\>java ByteBufferClear
Before clear method data in buffer
import java.nio.ByteBuffer;
import java.nio.channels.F
After clear method data in buffer

Download this code


Posted on: July 24, 2010 If you enjoyed this post then why not add us on Google+? Add us to your Circles

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