Count chars in Java

CountChars.java

import java.util.Random;

public class CountChars {
    static char[] chars;
    static int[] count;
    static String[][] graph;
    public static void main(String args[]) {
        chars = new char[100];
        count = new int[26];
        rand_char(chars);
        for(int i = 0; i < chars.length; i++) {
            /*if(i % 52 == 0) {
                System.out.println();
            }
            System.out.printf("%c ",chars[i]);*/
            count[(int)chars[i] - 'a']++;
        }
        System.out.println("\n");

        graph = new String[max(count) + 2][count.length];

        for(int i = 0; i < graph.length; i++) {
            for(int j = 0; j < graph[i].length; j++) {
                graph[i][j] = "  ";
            }
        }

        // assign value to graph
        for(int i = graph.length - 1; i > 0; i--) {
            for(int j = 0; j < graph[0].length; j++) {
                for(int k = 0; k < count[j]; k++) {
                    graph[graph.length - 1 - k][j] = " *";
                }
                //graph[graph.length - 1 - count[j]][j] = String.format("%2d", count[j]);
            }
        }

        for(int i = 0; i < graph.length; i++) {
            for(int j = 0; j < graph[0].length; j++) {
                System.out.print(" " + graph[i][j] + " ");
            }
            System.out.println();
        }

        for(int i = (int)'a'; i <= (int)'z'; i++) {
            System.out.print("----");
        }
        System.out.println();
        for(int i = (int)'a'; i <= (int)'z'; i++) {
            System.out.printf("  %c ", (char)i);
        }
        System.out.println();
    }

    public static int max(int[] c) {
        int max = c[0];
        for(int e: c ) {
            max = (e > max) ? e : max;
        }
        return max;
    }

    public static void rand_char(char[] c) {
        Random rand = new Random();
        for(int i = 0; i < c.length; i++) {
            c[i] = (char)(rand.nextInt((int)'z' - (int)'a' + 1) + (int)'a');
        }
    }
}