The Java 6 method String java.net.IDN.toASCII(String) drops the final input character if it is a dot (or equivalent, see RFC3490 3.1 1)
This causes problems for authority and domain validation.
This problem has been seen in
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609)
Java(TM) SE Runtime Environment (build 1.7.0_65-b17)
but appears to be fixed in
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Note also that the Java 8 version throws
java.lang.IllegalArgumentException: Empty label is not a legal name
if the argument contains two consecutive dots.
Fix to follow.