Duplicate Elements Find out From An Array Using Java?

Write a Program To Find The Duplicate Elements In An Array?

package com.java.Softwaretestingblog;
import java.util.HashSet;
public class ArrayDuplicate {
   public static void main(String[] args) {
      // TODO Auto-generated method stub
      String[] strArr = {"one","two","three","four","four","two","five"};
      HashSet<String> unique = new HashSet<String>();
      for(String str:strArr)
      {
         if(unique.add(str))
         {
            continue;
         }
         else
            System.out.println("Duplicate Entry is: "+str);
      }
   }
}

Let’s Execute The Above Duplicate Elements Program

Check Also: Program to Print Default Array Value

Results:

Duplicate Entry is: four
Duplicate Entry is: two

Another Solution

package com.java.interviewFAQ;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class RemoveDuplicateFromArray 
{
   public static void main(String[] args) 
   {
      // A string array with duplicate values
      String[] data = { "E", "C", "B", "E", "A", "B", "E", "D", "B", "A" };

      System.out.println("Original array         : " + Arrays.toString(data));
      List<String> list = Arrays.asList(data);
      System.out.println(list.size());
      Set<String> set = new HashSet<String>(list);
      System.out.print("After removing duplicates: ");
      System.out.println(set.size());
      String[] resarray= new String[set.size()];
      set.toArray(resarray);
      for (String ele: resarray) 
      {
         System.out.print(ele + ", ");
      }
   }
}