Simple flip a coin Java Program

Ok, so, I'm bored like most people, and I decided to play and create different apps to build on my java programming skills.

I'm currently stumped on this flip a coin program. I am using a Random number class and asking it to add up the total heads/amount of flips.... but it's not working.

Any hints would be helpful. Currently taking my first Java Class and a University student, so don't judge too much :)

import java.util.*;
public class FlipaCoin
{
 public static void main(String [] args)
 {
Random rand= new Random();
boolean a;
  while (a=true)
  {
int flip=rand.nextInt(2);
int heads=0;
  if (flip==1)
  {

    heads++;
}
double count=0;
double percentage=heads/count;
System.out.println(percentage);
count++;
  if (percentage==50.0)
  {
  break;
}
}
}
}