Remove duplicates from strings in Java

I tried to traverse a string to remove duplicate characters

For example, string aabbccdef should become ABCD EF and string ABCD should become ABCD

This is me so far

public class test {

    public static void main(String[] args) {

        String input = new String("abbc");
        String output = new String();

        for (int i = 0; i < input.length(); i++) {
            for (int j = 0; j < output.length(); j++) {
                if (input.charAt(i) != output.charAt(j)) {
                    output = output + input.charAt(i);
                }
            }
        }

        System.out.println(output);

    }

}

What is the best way to do this?

Solution

Convert the string to a char array and store it in the linkedhashset This will protect your order and remove duplicates It's like:

String string = "aabbccdefatafaz";

char[] chars = string.tocharArray();
Set<Character> charSet = new LinkedHashSet<Character>();
for (char c : chars) {
    charSet.add(c);
}

StringBuilder sb = new StringBuilder();
for (Character character : charSet) {
    sb.append(character);
}
System.out.println(sb.toString());