CustomerComparator customercomparator = new CustomerComparator(this); //assumes this is a Customer object
Arrays.sort(myArray, customercomparator); 

/** Inner class that implements Comparator interface.
*/
class CustomerComparator implements Comparator{

   Customer customer;

   public CustomerComparator(Customer customer){
      this.customer = customer;
   }

   public int compare(Object obj1,Object obj2){
          int result = -1;
          Customer c1=(Customer) obj1;
          Customer c2=(Customer) obj2;
          if(c1.amount < c2.amount) result = -1;
          if(c1.amount == c2.amount) result = 0;
          if(c1.amount > c2.amount) result = 1;
          return result;
   }

   public boolean equals(Object obj){
        Customer c=(Customer) obj;
        return (customer.amount == c.amount);
   }

}