java - Trying to understand following code for reversing a sentence -

please consider code below:

public class sentencereversal {      /**      * @param args      */     public static void main(string[] args) {           string[] parts = "this interview question".split("\\b");         stringbuilder sb = new stringbuilder();         (int = parts.length; --> 0 ;) {             sb.append(parts[i]);         }         system.out.println("[" + sb.tostring() + "]");  } } 

what "\b" doing in split function? removing producing following result(that means using split("")):

[noitseuq weivretni na si siht]

also, `-->' operator doing in loop? didn't quite understand. please me in understanding questions.

thanks

string.split() splits string based on regular expression.

\b regex expression , denotes word boundary i.e. start of line, end of line, space, punctuation marks etc. it's passed \\b because java needs \ escaped \.

when split() "" you're splitting on nothing , hence input string gets broken individual letters in array gets iterated in reverse , hence string of letters (instead of words) reversed.

just elaborate on @luiggimendoza's observations

i --> 0 // gets interpreted i-- > 0 // i.e. uses post-fix decrement operator 

which means value of i gets comapred 0 first , i = - 1 happens.

also, notice use of stringbuilder instead of stringbuffer (thread-safe slow) or plain string concatenation (would have created many unnecessary strings in java string pool).