Groovy file show errors when including java sql code

Have DB Statements in the groovy file using java.
In the code editor its showing red error icon in left with a message unable to resolve the preparedstatement. When I ignore this error and run the script it works. Why I get these warnings as i include java sql package.

import java.sql.*;
 String querySel="SELECT count(*) FROM `test` WHERE code=?";
 PreparedStatement preparedStmt = connection.prepareStatement(querySel);

could anyone help me regarding this?