Regex ignore tokens that do not start with letter

how can I write a regex that ignores any token that does not start with a letter? it should be used in java.

example: it 's super cool --> regex should match: [it, super, cool] and ignore ['s].

You can use (?<!\\p{Punct})(\\p{L}+) which means letters not preceded by a punctuation mark. Note that (?<! is used to specify a negative look behind. Check the documentation of Pattern to learn more about it.

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
	public static void main(String[] args) {
		String str = "it 's super cool";
		Pattern pattern = Pattern.compile("(?<!\\p{Punct})(\\p{L}+)");
		Matcher matcher = pattern.matcher(str);
		while (matcher.find()) {
			System.out.println(matcher.group());
		}
	}
}

Output:

it
super
cool

Alternative regex:

"(?:^|\\s)([A-Za-z]+)"

Regex in context:

public static void main(String[] args) {
    String input = "it 's super cool";
    Matcher matcher = Pattern.compile("(?:^|\\s)([A-Za-z]+)").matcher(input);
    while (matcher.find()) {
        String result = matcher.group(1);
        System.out.println(result);
    }
}

Output:

it
super
cool

Note: To match alphabetic characters, letters, in any language (e.g. Hindi, German, Chinese, English etc.), use the following regex instead:

"(?:^|\\s)(\\p{L}+)"

More about the class, Pattern and the classes for Unicode scripts, blocks, categories and binary properties, can be found here.