Write a Java Program to find the duplicate characters in a string.

In this program, we have created a string variable str and initialized an integer count with zero.

Then, we have created a character array to convert our string variable to the character. With the help of for loop, we are performing a comparison between different character at different indexes.

If two character of consecutive index matches, then it will print that character and the counter will be incremented by 1 after each iteration.

1	public class DuplicateCharacters {

2

3	public static void main(String[] args) {

4	// TODO Auto-generated method stub

5	String str = new String("Sakkett");

6	int count = 0;

7	char[] chars = str.toCharArray();

8	System.out.println("Duplicate characters are:");

9	for (int i=0; i<str.length();i++) {

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

11	if (chars[i] == chars[j]) {

12	System.out.println(chars[j]);

13

count++;

14

break;

15

}

16

}

17

}

18

}

19

20

}

Output:

Duplicate characters are:
k
t