How to get matching characters in a string in java?

There are following way to get matching characters in a string in java.

• We take a string word.
• Create a HashSet Object of String type.
• Now get the Stream data from Arrays.stream() method.
• Break the string word from split method.
• In filter method we are adding duplicate word inside HashSet.
• From Collectors.toSet() method we are collect only unique data.
• Now print the character value.

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.stream.Collectors;

public class MatchChar {

	public static void main(String[] args) {
		String str = "wweelcomee";
		Set<String> hs = new HashSet<String>();
		Set<String> matchChar = Arrays.stream(str.split("")).filter(s -> !hs.add(s))
				                .collect(Collectors.toSet());
		System.out.println("matching character is:- " + matchChar);

	}
}

output:- matching character is:- [e, w]