title: Understanding mysterious Oracle JDBC errors - ORA-00911: invalid character
body: <p>I am making Java 1.6-JDBC-Oracle 11 code. I created a table called employee with id,name and age. I am getting the error - ORA-00911: invalid character. How can I fix this ?</p>
  
  <p>Here is my code-</p>
  
  <pre><code>import java.sql.*;
  import java.util.Properties;
  import java.io.IOException;
  import java.io.FileInputStream;
  
  public class HelloOracle {
  
      static String query =
          "SELECT emp_id, emp_name, emp_age " +
          "FROM employee;";
  
      public static void main(String[] args) {
          String username = "";
          String password = "";
          Properties prop = new Properties();
          try {
              FileInputStream fis = new FileInputStream("Login.properties");
              prop.load(fis);
          } catch (IOException ex) {
              ex.printStackTrace();
          }
  
          username = prop.getProperty("username").trim();
          password = prop.getProperty("password").trim();
  
          try {
              Connection con = DriverManager.getConnection("jdbc:oracle:thin:@//localhost:1521/xe", username, password);
  
              Statement stmt = con.createStatement();
  
              ResultSet rs = stmt.executeQuery(query);
  
              while (rs.next()) {
                  System.out.print(rs.getString("emp_id"));
                  System.out.print("  ,  ");
                  System.out.print(rs.getString("emp_name"));
                  System.out.print("  ,  ");
                  System.out.print(rs.getString("emp_age"));
                  System.out.println();
              }
          } catch (SQLException e) {
              System.out.println("Exception: " + e);
          }
  
      }
  
  }
  </code></pre>
  
  <p>Unfortunately, oracle error messages are not as informative as mysql or mssql and I am not able to trouble shoot them easily. I am also not able to see which line of code caused the exception.</p>