Creating a very large file using mapping

// : c12:LargeMappedFiles.java
// Creating a very large file using mapping.
// {RunByHand}
// {Clean: test.dat}
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

public class LargeMappedFiles {
  static int length = 0x8FFFFFF; // 128 Mb

  public static void main(String[] args) throws Exception {
    MappedByteBuffer out = new RandomAccessFile("test.dat", "rw")
        .getChannel().map(FileChannel.MapMode.READ_WRITE, 0, length);
    for (int i = 0; i < length; i++)
      out.put((byte) 'x');
    System.out.println("Finished writing");
    for (int i = length / 2; i < length / 2 + 6; i++)
      System.out.print((char) out.get(i));
  }
} ///:~

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15.	Mapping an entire file into memory for reading
16.	Mapped IO
17.	What happens when the entire file isn't in your mapping region
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Creating a very large file using mapping : Input Output Stream « File Input Output « Java

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