import java.util.ArrayList;
import java.util.List;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
 
public class Main {
	public static void main(String[] args) {
		String str = "this is a test of proper nouns @Ryan";
 
		List<String> list = Pattern.compile("@?\\w+|\\b(?!$)")
                .matcher(str)
                .results()
                .map(MatchResult::group)
                .collect(Collectors.toList());
 
		System.out.println(list);
 
		// #############Non-Stream Solution#############
		Matcher matcher = Pattern.compile("@?\\w+|\\b(?!$)").matcher(str);
		List<String> parts = new ArrayList<>();
		while (matcher.find()) {
			parts.add(matcher.group());
		}
 
		System.out.println(parts);
	}
}

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