Java by API/java.nio.channels/Channels

Channels: newInputStream(ReadableByteChannel ch)

 
import java.io.File;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
public class Main {
  public static void main(String[] argv) throws Exception {
    // Create a read/writeable file channel
    File file = new File("filename");
    FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
    InputStream is = Channels.newInputStream(channel);
    // Close the channel
    is.close();
  }
}

Channels: newOutputStream(WritableByteChannel ch)

 
import java.io.File;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
public class Main {
  public static void main(String[] argv) throws Exception {
    // Create a read/writeable file channel
    File file = new File("filename");
    FileChannel channel = new RandomAccessFile(file, "rw").getChannel();
    OutputStream os = Channels.newOutputStream(channel);
    os.close();
  }
}