Testing regex with Java

Question

I'm learning regex and I'm using the following code snippet for testing purpose:

String regex = "";
String test = "";
Pattern.compile(regex).matcher(test).find();

but when I try some like this:

System.out.println(Pattern.compile("h{2,4}").matcher("hhhhh").find()); 

it returns true and not false as expected.

or

System.out.println(Pattern.compile("h{2}").matcher("hhh").find());

it returns true and not false as expected.

What's the problem? Maybe this is not the right statements to use for testing correctly the regex?

thanks.

Answer 1

The string hhh contains two hs, therefore the regex matches since the find() method allows matching of substrings.

If you anchor the regex to force it to match the entire string, the regex will fail:

^h{2}$

Another possibility would be to use the matches() method:

"hhh".matches("h{2}")

will fail.