Oracle JDBC -- How to clean up an orphan session after reconnection?

I am using Oracle 8.1.7 JDBC thin driver and Java 1.4.2.

My application tries reconnection after a connection is dropped. Once reconnection succeeds, the application repeats an operation.

The scenario is:

App updates table Employee.
The network between App and Oracle is down.
Commit fails.
The network resumes.
Rollback fails (due to socket write error).

App reconnects.
App updates table Employee again.
App waits for a table lock (since the previous session is still alive in Oracle).

The code is:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class App {

    private Connection conn;

    private void connect() {
        //  Assume connection always succeeds.
        try {
            conn = DriverManager.getConnection(
                    "jdbc:oracle:thin:@localhost:1521:db1", "dummy",
                    "foo");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    private void reconnect() {
        //  Assume reconnection always succeeds.
        try {
            conn = DriverManager.getConnection(
                    "jdbc:oracle:thin:@localhost:1521:db1", "dummy",
                    "foo");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public App() throws Exception {
        DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
        connect();
    }

    public void doSomeUpdate() {
        try {
            conn.setAutoCommit(false);
            Statement stmt = conn.createStatement();
            stmt.executeUpdate("UPDATE Employee SET salary = 100 WHERE name = 'Mary'");
            // The network between App and Oracle is down at this point of time.
            conn.commit();
        } catch (SQLException e) {
            try {
                // The network between App and Oracle resumes at his point of time.                
                conn.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            reconnect();
            doSomeUpdate();
        }
    }

    public static void main(String[] args) {
        try {
            new App().doSomeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The problem is:

(1) How to kill an orphan session in Java after reconnection?

(2) How to get the SID and serial# of a session associated with a JDBC connection in Java?

(3) Any better way to gracefully do reconnection?

Thanks and Regards,
Matt