find frequency of characters

public class FrequencyCharacter     
{    
     public static void main(String[] args) {    
        String str = "picture perfect";    
        int[] freq = new int[str.length()];    
        int i, j;    
            
        //Converts given string into character array    
        char string[] = str.toCharArray();    
            
        for(i = 0; i