How to eliminate duplicates from an array?

Answers were Sorted based on User's Feedback

Answer / manju

by using HashSet(Collection name)

Is This Answer Correct ?    33 Yes 1 No

Answer / edward sudhaharchennai

Unlike other implementations of the collection interface,
implementation of the Set intrface do not allow duplicate
elements. This also means that a set can contain at most
one null value. The set interface does not define any new
methods, and its add() and addAll() methods will not store
duplicates. If an element is not currently in the set, two
consecutive calls to the add() method to insert the element
will first return true then false...........

Is This Answer Correct ?    6 Yes 2 No

Answer / gajendra

using hash map or treeset of collection framework

Is This Answer Correct ?    8 Yes 5 No

Answer / qim2010

Using HashSet class we can eliminate duplicates from and
array. Here is a simple example

public class ArrayRemoveDuplicate {
public static void main(String[] args) {
// A string array with duplicate values
String[] data = {"A", "C", "B", "D", "A", "B", "E",
"D", "B", "C"};
System.out.println("Original array : " +

// Convert it to list as we need the list object to
create a set object.
// A set is a collection object that cannot have a
duplicate values, so
// by converting the array to a set the duplicate
value will be removed.
List<String> list = Arrays.asList(data);
Set<String> set = new HashSet<String>(list);

System.out.print("Remove duplicate result: ");

// Create an array to convert the Set back to array.
The Set.toArray()
// method copy the value in the set to the defined
String[] result = new String[set.size()];
for (String s : result) {
System.out.print(s + ", ");

Is This Answer Correct ?    4 Yes 1 No

Answer / vijaya bhaskar teegala

use linkedHashSet.It will maintain the insertion order

Is This Answer Correct ?    1 Yes 1 No

Answer / elango boopathy

package com.sample.pack;

import java.util.ArrayList;
import java.util.List;

public class Duplicates {

* @param args
public static void main(String[] args) {
// TODO Auto-generated method stub
int k = 1;
String[] str = { "abc", "123", "tyu", "xyz", "123", "m",
"abc", "abc" };
boolean isDuplicate = false;
List<String> list = new ArrayList<String>();

for (int i = 0; i < str.length; i++) {
for (int j = k; j < str.length; j++) {
if (str[i].equals(str[j].toString())) {
isDuplicate = true;
k = k + 1;
if(isDuplicate == false){

isDuplicate = false;
Object[] afterDuplicate = list.toArray();
for(int i=0; i<afterDuplicate.length; i++){


Is This Answer Correct ?    0 Yes 0 No

Post New Answer

More Core Java Interview Questions

To what value is a variable of the Boolean type automatically initialized?

3 Answers  

What is clipping?

2 Answers  

how to deploy tomcatserver to weblogic server? write d following steps?

0 Answers  

Can i have abstract class with no abstract methods?

22 Answers   CTS,

what is the use of StringBuffer?

2 Answers   Accenture,

How to count occurrences of each duplicate element in a list {a,b,d,c,a,b} ? Thanks in Advance

2 Answers   TCS,

1).what is the difference between below examples String s="vijay"; String s=new String("vijay");

12 Answers   Satyam, TCS, Mascon,

How is Garbage collection done in Java?

3 Answers   T3 Softwares,

can any body tell me? does advance java and j2ee both are same.

4 Answers   CTS, Infosys,

system.out.println(1 + 3);

8 Answers  

hi am an engineering student and my next plan is for ms in either in us or australia i got my passport but i dont know anything bout visa can u give brief idea 1)How to get prepared for visa and 2)How to apply for top universities and 3)How to pay the fee and so on These all are basic questions plz give me a clear idea

0 Answers  

What is an enumeration class?

2 Answers