Java Database Connectivity (JDBC)

import java.sql.DriverManager;

public class Connection {
	
	public static Connection getDatabaseConnection(){
		Connection con = null;
		try{
			// load the driver
			DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
			// get the connection
			con = DriverManager.getConnection ("jdbc:oracle:thin:@localhost:1521:bob", "scott", "tiger");

			if(con != null){
				System.out.println("Connection established Successfully at port : "+1521);
			}else{
				System.out.println("Could not establish Connection");
			}
		}
		catch (Exception e){
			e.printStackTrace();
			con = null;
		}
		return con;
	 }

}

Error pointing on line

con = DriverManager.getConnection ("jdbc:oracle:thin:@localhost:1521:bob", "scott", "tiger");

Type Mismatch: Cannot convert from Connection to Connection

I have included the classes12.jar file as an external Jar file for the project.