Here is a code that count the number of constants from the input string.

import java.util.*;

class StringExample 
{
public static void main(String[] args) 
    {
        Scanner input=new Scanner(System.in);
        System.out.print("Enter string:");
        String str=input.nextLine();
        char ch[]=str.toCharArray();
        int count=0;
        for(int i=0;i<ch.length;i++){
            if(ch[i]=='a'||ch[i]=='e'||ch[i]=='i'||ch[i]=='o'||ch[i]=='u'){

            }
            else if(ch[i]==' '){
            }
            else{
                count++;
            }
        }
        System.out.println("Number of constants: "+count);

    }
}