loadjava -v -r user_name/pass@sid -r jxl.jar

create or replace and compile java source named Test as

import java.io.File;
import jxl.Workbook;

public class Test
{
  public static void entry(String fileName)
  {
      File xlsFile = new File(fileName);
      Workbook workbook = Workbook.getWorkbook(xlsFile);
  }
}

Compilation errors for JAVA SOURCE SCOTT.TEST

Error: cannot access jxl.Workbook
Line: 4
Text: import jxl.Workbook;