Splitting text by whitespaces headache 😤😥

Question

Hello learners!!
If somebody can help....
❓ Why String#split or Pattern#split return one result more on empty string or with trailing whitespaces?
🤔🤔🤔
"".split("\\s+").length == 1
" ".split("\\s+").length == 0
" Hello learners".split("\\s+").length == 3
" Hello learners ".split("\\s+").length == 3
❓ There are any regex to solve it? I mean, some using non capture groups or look ahead/behind capture modifiers combination to bypass it.
I try it but without success 😥. E.g.:
(?:^\\s+)\\s+
https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/util/regex/Pattern.html
At this moment I hack it doing a trim() before but I wish know other options... mastering on regular expressions.
Testcase Template 👇
https://code.sololearn.com/ckmNb74UCnqr/?ref=app
Where I want to apply it 👇
https://code.sololearn.com/cd7dRTk2331T/?ref=app

Answer 1

Try using a Matcher.
https://code.sololearn.com/c3A15a19A16A/?ref=app

Answer 2

Coder Kitten thanks for your contributions
I update the post description with a TESTCASE template
Yes, Is a bit extrange because in StringTokenizer class encourage using String#split but with this mentioned cases aren't the same 😣.
https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/util/StringTokenizer.html
Of course because the almost core classes like that, Scanner... uses internally a Matcher and then, you have to pass the contrary regex definition used in a split method)
[^\\s]+