public interface Basic_IO {
	int read(int, byte[], int);
	int write(int, byte[], int);
}
public interface Buffered_IO extends Basic_IO {
	int buf_read(int, byte[], int);
	int buf_write(int, byte[], int);
}
public interface File_IO extends Basic_IO {
	int file_read(int, byte[], int, int);
	int file_write(int, byte[], int, int);
}
public class File extends SomeClass implements Buffered_IO, File_IO {
	public int read(int fd, byte[] buf, int count) { ... }
	public int write(int fd, byte[] buf, int count) { ... }
	public int buf_read(int fd, byte[] buf, int count) { ... }
	public int buf_write(int fd, byte[] buf, int count) { ... }
	public int file_read(int fd, byte[] buf, int count, int off) { ... }
	public int file_write(int fd, byte[] buf, int count, int off) { ... }
}