You could use something like this:

public class ConnectionHolder {
       
       private static Connection con;

       public static Connection getConnection() {
               if(con == null) {
                       con =   //create the connection as you would otherwise
               }
               return con;
       }
}

Now, everytime you need the connection, you do like this:

Connection con = ConnectionHolder.getConnection();
//work with the connection

This will break once you start to use your connection from within several
threads though. In that case, you'd have to setup a Datasource or a
ConnectionPool.