import java.io.*;

public class RandomAccessFileTest {
	public static void main(String[] args) throws Exception {
		String homedir = System.getProperty("user.home");
		File dbdir = new File(homedir, "testdb");
		File dbfile = new File(dbdir, "testfile");

 		RandomAccessFile f = new RandomAccessFile(dbfile, "rw");
 		f.seek(20);
 		f.writeInt(345);
 		String s = "xyz";
 		byte[] sbytes = s.getBytes();
 		int slen = sbytes.length;
 		f.seek(40);
 		f.writeInt(slen);
 		f.write(sbytes);

 		f.seek(20);
 		System.out.println("value at location 20 = " + f.readInt());
 		f.seek(40);
 		int newslen = f.readInt();
 		byte[] b = new byte[newslen];
 		f.read(b);
 		String s2 = new String(b);
 		System.out.println("value at location 40 = " + s2);
	}
}