java - Remove duplicate chars from a String recursively -

i need figure how can remove duplicates chars string. has done recursively real problem..

public class feq2 {     /**      * @param args      */     public static void removedups(string s, int firstchar, int secondchar) {             if (s.length() == 1) {               system.out.println(s);         }                    char = s.charat(firstchar);         if (a == s.charat(secondchar)) {             s = + s.substring(secondchar + 1);         }         system.out.println(s);         removedups(s, firstchar + 1, secondchar + 1);         //return s;     }      public static void main(string[] args) {         //system.out.println(removedups("aaaabbarrrcc", 1));         removedups("aaaabbarrrcc", 0 , 1);     } } 

you can this:

public static string removedups(string s) {     if ( s.length() <= 1 ) return s;     if( s.substring(1,2).equals(s.substring(0,1)) ) return removedups(s.substring(1));     else return s.substring(0,1) + removedups(s.substring(1)); }   input: "aaaabbarrrcc" output: "abarc" 

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edit: way

public static string removedups(string s) {     if ( s.length() <= 1 ) return s;     if( s.substring(1).contains(s.substring(0,1)) ) return removedups(s.substring(1));     else return s.substring(0,1) + removedups(s.substring(1)); }   input: "aaaabbarrrcc" output: "barc" 

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edit: 3rd way

public static string removedups(string s) {     if ( s.length() <= 1 ) return s;     if( s.substring(0,s.length()-1).contains(s.substring(s.length()-1,s.length())) ) return removedups(s.substring(0,s.length()-1));     else return removedups(s.substring(0,s.length()-1)) + s.substring(s.length()-1,s.length()); }   input: "aaaabbarrrcc" output: "abrc"