My RConnection produces an error

//import org.rosuda.REngine.REXP;
//import org.rosuda.REngine.Rserve.RConnection;
public class RConnectionFromJava {

  public static void main(String args[])
  {
    try{

      System.out.println("INFO: Trying to connect to R ");
      RConnection c = new RConnection();
      System.out.println("INFO: Connected to R ");
      System.out.println("INFO: The Server version is "+ c.getServerVersion());

      c.close();
    }
    catch(Exception e)
    {
      System.out.println("ERROR: 开发者_开发技巧In Connection to R ");
      System.out.println("The Exception is "+ e.getMessage());
      e.printStackTrace();
    }
  }
}

This gives an error for RConnection. Could you please tell me why it gives this error?

Remove // before import org.rosuda.REngine.Rserve.RConnection;