IDN.toASCII method is failing on processing input parameter with leading dots
- IllegalArgumentException: "Empty label is not a legal name".

See test example:

import java.net.IDN;

public class IDNTest {

  public static void main(String[] args) {

    String okString = ".";
    String failString = ".abc";

    try {
      System.out.println(IDN.toASCII(okString)); // OK
      System.out.println(IDN.toASCII(failString)); // Exception
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

}

Same code was working fine in JDK7.