Random java.lang.StackOverflowError

[GoogleCodeExporter]

What steps will reproduce the problem?

1. Run following code couple of times. Usually exception is thrown between 
first and tenth iteration:

import nl.flotsam.xeger.Xeger;

public class Test {
    public static void main(String[] args) {
        String pattern = "[\\w\\-.]+(@[a-zA-Z0-9.\\-]+\\.[a-zA-Z0-9]{2,})?";
        Xeger generator = new Xeger(pattern);
        for (int i = 0; i < 1000; i++) {
            System.out.println("iteration " + i);
            generator.generate();
        }
    }
}


What is the expected output?
String according to passed pattern.

What do you see instead?
java.lang.StackOverflowError

What version of the product are you using? On what operating system?
1.0, Red Hat Enterprise Linux Client release 5.4 (Tikanga)

Please provide any additional information below.

Output:

iteration 0
iteration 1
iteration 2
iteration 3
iteration 4
Exception in thread "main" java.lang.StackOverflowError
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:587)
    at java.lang.StringBuilder.append(StringBuilder.java:214)
    at nl.flotsam.xeger.Xeger.appendChoice(Xeger.java:85)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:79)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
    at nl.flotsam.xeger.Xeger.generate(Xeger.java:80)
...

Original issue reported on code.google.com by [email protected] on 24 Mar 2015 at 10:50