public class Security {   
  // Attribute Data members   
  private String symbol;   
  private String companyName;   
  private float currentPrice;   
  private float askPrice;   
  private float bidPrice;   
  // Relationship Data Members
  // Set of transactions for this security   
  private Vector<Transaction> transactions;
}

      public class Member {   
        // Attribute Data members   
        private String mid;   
        private String password;   
        private String fname;   
        private String lname;   
        private String address;   
        private String email;   
        private double cashBalance;   
        // Relationship Data Members   
        // Set of transactions for this member
        private Vector<Transaction> transactions;
      }

      public class Transaction {   
        // Attribute Data members   
        private Date transDate;   
        private String transType; // Buy or Sell   
        private float quantity;   
        private float pricePerShare;   
        private float commission;   
        // Relationship Data Members   
        private Member member; // member for this transaction   
        private Security security; // security for this transaction 
}