Remove Duplicate From String - Java & Python

PYTHON:

a = "raman rayat"
aa = ""
for i in range(len(a)):
flag = False
for j in range(len(aa)):
if a[i]==a[j]:
flag=True
break
if flag==False:
aa=aa+a[i]
print(aa)

JAVA: 

#1 using array

public class test1 {
    public static void main(String[] args) {
        String s = "abcdabccdb";
        String s2 = "";
        for (int i = 0; i < s.length(); i++) {
            Boolean found = false;
            for (int j = 0; j < s2.length(); j++) {
                if (s.charAt(i) == s2.charAt(j)) {
                    found = true;
                    break;
                }
            }
            if (found == false) {
                s2 = s2.concat(String.valueOf(s.charAt(i)));
            }
        }
        System.out.println(s2);
    }

}

#2 using linked hash set

import java.util.LinkedHashSet;
import java.util.Set;

public class test1 {
    public static void main(String[] args) {

        String text = "ramanrayat";
        String newtext="";
        
        Set<Character> hs = new LinkedHashSet<>();
        for(int i =0;i <text.length();i++){
            hs.add(text.charAt(i));
        }
        
        for(Character c: hs){
            newtext=newtext+c;
        }
        System.out.println(newtext);

    }
}

#3 using set 

import java.util.LinkedHashSet;
import java.util.Set;

public class remove_duplicates_char_2 {
    public static void main(String args[]) {
        String val = "raman";
        char[] val2 = val.toCharArray();
        Set<Character> s1 = new LinkedHashSet<>();
        for(Character s2: val2){
            s1.add(s2);
        }
        System.out.println(s1);

        StringBuffer sb = new StringBuffer();
        for(Character ch: s1){
            sb.append(ch);
        }
        System.out.println(sb);
    }
}

 

#4 : using contains 

public class test1 {
    public static void main(String[] args) {

        String text = "ramanrayat";
        String newtext = "";

        for(int i=0;i<text.length();i++){
            if(!newtext.contains(String.valueOf(text.charAt(i)))){
               newtext=newtext+text.charAt(i);
            }
        }
        System.out.println(newtext);
    }
}