java - Regular Expression program from Predefined character classes - 


public class regularexpressiondemo2 {      public static void main(string[] args) {         pattern p = pattern.compile("\\.");         matcher m = p.matcher("a1b7 @z#");         while (m.find()) {             system.out.println(m.start() + "-------" + m.group());         }     } }

from docs, says . symbol prints character how come above program doesn't print thing.

you double-escaped dot.

this means matching literal dot, not wildcard character.

your input not contain one, hence nothing gets printed.

change pattern ".".


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