Java program to find duplicate strings present in a sentence

Given String: This is Rajneesh This and will That is This

Required OUTPUT: This, is

---------------------------------------------------------

Source File: DuplicateString.java

package String_Programs;

import java.util.ArrayList;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

public class DuplicateString {

      

       public static void duplicateString(String str){

             

              Set<String> duplicateSet = new HashSet<String>()

              List<String> duplicateList = new ArrayList<String>();

              String[] strArray = str.split(" ");

             

              for(int i=0;i<strArray.length;i++){

                     for(int j=i+1;j<strArray.length;j++){

                           if(strArray[i].equals(strArray[j])){

                                  //if(duplicateList.contains(o))

                                  duplicateSet.add(strArray[i]);

                                  duplicateList.add(strArray[i]);

                           }

                     }

              }

             

              System.out.println("List bucket data :" +duplicateList);

              System.out.println("Set bucket data :"  +duplicateSet);

       }

       public static void main(String[] args) {

              duplicateString("This is Rajneesh This and will That is This");

       }

}

OUTPUT: 

List bucket data :[This, This, is, This]

Set bucket data :[This, is]

The output between List and Set calls for a discussion. Have a look and try to figure out what's the difference?