"Stupid design of regular expression in java"

Question

I bet majority will stumble on this:
String inputStr = "a,,b";
String patternStr = ",";
String[] fields = inputStr.split(patternStr);
result: ["a", "", "c"]
so if inputStr = ,,
then result: ["","",""] ??
If you think so, give yourself a treat.
Now give yourself a bigger treat. cause
the result is [""]
Unbelievable about inconsistency of regular expression.
It look so irregular.

Answer 1

Take a look at the site which quote
http://www.devarticles.com/c/a/Java/Regular-Expressions/10/
Perl is probably the most popular language to offer regular expression support. As such, it makes sense to put Java’s regex support in context by comparing it to that of Perl. The distinctions you should be aware of are highlighted in the sections that follow. Generally speaking, J2SE doesn’t include some Perl constructs, because Java is a full-featured programming language that offers sophisticated condition and logical paths of execution that are reasonable alternatives to the constructs offered by Perl."
Since, Java doesn't offer means it is perl, why not fix the "weirdness" of perl is in this case ? let the split function work as intended.
Check this out from Java almanac
// Parse a comma-separated string
String inputStr = "a,,b";
String patternStr = ",";
String[] fields = inputStr.split(patternStr);
// ["a", "", "b"]
// Parse a line whose separator is a comma followed by a space
inputStr = "a, b, c,d";
patternStr = ", ";
fields = inputStr.split(patternStr, -1);
// ["a", "b", "c,d"]
// Parse a line with and's and or's
inputStr = "a, b, and c";
patternStr = "[, ]+(and|or)*[, ]*";
fields = inputStr.split(patternStr, -1);
// ["a", "b", "c"]
Everything is mentions except to solve the common issue I have.
http://javaalmanac.com/egs/java.util.regex/ParseLine.html
The above will failed if any empty data within pipe. It is how you manage to detect the empty data that is relatively important because it screw up your program. And too code to do that increase your chance of program error.
Sometimes we just accept thing but never question why there aren't better way.