Example Depot

try {
    File file = new File("filename");

    // Create a read-only memory-mapped file
    FileChannel roChannel = new RandomAccessFile(file, "r").getChannel();
    ByteBuffer roBuf = roChannel.map(FileChannel.MapMode.READ_ONLY, 0, (int)roChannel.size());

    // Create a read-write memory-mapped file
    FileChannel rwChannel = new RandomAccessFile(file, "rw").getChannel();
    ByteBuffer wrBuf = rwChannel.map(FileChannel.MapMode.READ_WRITE, 0, (int)rwChannel.size());

    // Create a private (copy-on-write) memory-mapped file.
    // Any write to this channel results in a private copy of the data.
    FileChannel pvChannel = new RandomAccessFile(file, "rw").getChannel();
    ByteBuffer pvBuf = roChannel.map(FileChannel.MapMode.READ_WRITE, 0, (int)rwChannel.size());
} catch (IOException e) {
}