NumberFormat « JTextField « Java Swing Q&A

1. java.lang.NumberFormatException: For input string: ""    stackoverflow.com

When running this code:

JTextField ansTxt;
...
ansTxt = new JTextField(5);
String aString = ansTxt.getText();
int aInt = Integer.parseInt(aString);

Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: ""

JTextField ansTxt;
ansTxt = ...

2. JFormattedTextField accepting different number of digits    stackoverflow.com

I need a JTextField limiting to 3 decimal places. After a search, i discovered JFormattedTextField, which looks great. The code right now is:

try
{
    double aux = 25.4;
  ...

3. NumberFormat, Currency, JTextField    coderanch.com

Hello, I want to make a JTextField that will take input in and format it accordingly to the current locale's currency. The key here is that programmatically I need to detect what locales have decimal points. Additionally, I need the number input to start from the right. Furthermore, I have a somewhat working model for US currency but I would like ...