program to calculate product of each column in matrix

Write a java program to count how many times substring is present in Sentence : 

import java.util.Scanner;

public class CountSubString {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

System.out.println("Enter Sentence ");

String str = sc.nextLine();

System.out.println("Enter Substring : ");

String substr=sc.nextLine();

int count=toCountSubstring(str,substr);

System.out.println("Entered Substring is present "+count+" times");

}

private static int toCountSubstring(String str, String substr) {

char []string =str.toCharArray();

char []subst=substr.toCharArray();

int count=0;

for(int i=0;i<string.length;i++) {

int j=0,k=i;

while(k<string.length && j<subst.length && (string[k]==subst[j])) {

k++;

j++;

}

if(j==subst.length) {

count++;

}

}

return count;

}

}