java.lang.NumberFormatException: For input string: "" when using "2" or "5"

java.lang.NumberFormatException: For input string: "" when using "2" or "5"

I read in a menu choice and typing in any number but 2 & 5 work.
String choice = promptUser(choicePrompt);
try {
outputInfo(String.format("choice=...%s...",choice));
int c = Integer.parseInt(choice);
/* process it */
}catch (NumberFormatException e) {
outputInfo(String.format("choice=%s",choice));
outputInfo(e.toString());
}
public static void outputInfo(String msg)
{
System.out.printf("\t%s\n",msg);
}
Good output:
Enter Option: 1
choice=...1...
Bad Output:
Enter Option: 2
choice=...2...
choice=2
java.lang.NumberFormatException: For input string: ""
Any ideas gratefully received.
Simon