How to remove the java error "Class not found or loaded"?

Question

I have written a code snippet below and have saved it as Exerciselb.java and its compiled properly but its not executing

Snippet:

class Exerciselb {

    public static void main(String[] args){
        int x = 1;
        while (x < 10){
            System.out.println("Inside while loop");
            if ( x > 3) {
                System.out.println("big x");
            }
        }
    }
}