import java.sql.*;

public class updaters2 {

	public static void main(String args[]) throws Exception {
		Class.forName("org.postgresql.Driver");
		Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost:5750/jurka","jurka","");

		setupDB(conn);

		Statement stmt = conn.createStatement();

		ResultSet rs = stmt.executeQuery("SELECT * FROM mytesttable FOR UPDATE OF mytesttable;");
		rs.first();
		rs.updateString(2,"aaa");
		rs.updateRow();
		rs.previous();
		rs.updateString(2,"zzz");
		rs.updateRow();
		rs.close();
		stmt.close();
		conn.close();
	}

	private static void setupDB(Connection conn) throws SQLException {
		Statement stmt = conn.createStatement();
		try {
			stmt.executeUpdate("DROP TABLE mytesttable");
		} catch (SQLException sqle) {
			conn.rollback();
		}
		stmt.executeUpdate("CREATE TABLE mytesttable(a int primary key, b text)");
		stmt.executeUpdate("INSERT INTO mytesttable VALUES (1,'hello')");
	}

}