Find duplicate characters in a String and count the number of occurances using Java

Question

How can I find the number of occurrences of a character in a string?

For example: The quick brown fox jumped over the lazy dog.

Some example

Answer 1

If your string only contains alphabets then you can use some thing like this.

public class StringExample {
public static void main(String[] args) {
    String str = "abcdabghplhhnfl".toLowerCase();
    // create a integer array for 26 alphabets.
    // where index 0,1,2.. will be the container for frequency of a,b,c...
    Integer[] ar = new Integer[26];
    // fill the integer array with character frequency.
    for(int i=0;i1) {
            char c = (char) (97+i);
            System.out.println("'"+c+"' comes "+ar[i]+" times.");
        }
    }
}
}

Output:

 'a' comes 2 times.
 'b' comes 2 times.
 'h' comes 3 times.
 'l' comes 2 times.