How to remove the last new line in text area ?

Question

I have a calculator Applet that shows the calculation in a text area.
if i enter 2+6, the text area shows
2+
6
and i have a clear last button, which deletes the last entry by user.
in the example above, one hit of clear last, deletes 6. another hit should delete +.
I can delete the numbers, but I don't know how to go back to the previous line and delete the operator.
I may have other calculations in that text area above the current calculation. so replaceAll("\n","") would not work here.
Please someone help me here.

Answer 1

it's an applet, i am developing in Eclipse ( mac environment)
so for deleting a number i used this code, and works fine
String temp = t.getText();
                         String lastChar = temp.substring(temp.length()-1);
                         for (int i=0; i<numbers.length; i++) // deleting a number
                              if (lastChar.equals(numbers)){
                                   temp = temp.substring(0,temp.length()-1);
                                   number = number.substring(0,number.length()-1);
                                   t.setText(temp);
which t is the text area, and numbers is the string array of 0 to 9, and number is a string where i store the entered number
so i thought for deleting an operator i should use something similar, where i need to go back to the previous line and delete it,
String temp = t.getText();
                         String lastChar = temp.substring(temp.length()-1);
                         if(lastChar.equals("n")){
                                                        temp = temp.substring(0,temp.length()-3);// deleting n , \ , and the operator
                                   t.setText(temp);
                         } but it doesn't work