understanding buttons :JSP random no program

I hav java random no generator program but i need to implement it in JSP such that page generates random no between 100 and 200 on loading and on clicking submit button it ives message box or just shows on page "no is less"if it less then 150 else shows "no is greater" please help me to understand buttons .thank you java code for random no generation:

public class TestRandom
{
   public static void main(String args[]){
        Random r = new Random();
        int start = 100, end = 200; //The random number will be between 100 and 200
        for(int i=0;i<10;){ //suppose here 10 numbers ll be generated
            int rand = r.nextInt();
            if(rand>100 && rand<200){
                System.out.println(rand);
                i++;
            }
        }
    }
}