What is the default value for HashMap in Java?

Java error in creating multiple new objects?

• Write two classes: TestAccount and Account to represent an account. The class contains: a) An int data field named id for the account with value 100. b) A double data field named balance for the account with value 1000. c) A double data field named annualInterestRate that stores the current interest rate with value 0.1 d) The accessor method for id, balance, and annual InterestRate. Account.java public class Account { //attributes double id; double bal; double air; //default constructor public Account() { id = 0.0; bal = 0.0; air = 0.0; } //parameterized constructor (3 parameters) public Account (double id, double bal, double air) { Identity = id; Balance = bal; AnnualInterestRate = air; } public double Identity() { return id; } public double Balance() { return bal; } public double AnnualInterestRate() { return air; } } ERROR: Account.java:19: error: cannot find symbol Identity = id; ^ symbol: variable Identity location: class Account Account.java:20: error: cannot find symbol Balance = bal; ^ symbol: variable Balance location: class Account Account.java:21: error: cannot find symbol AnnualInterestRate = air; ^ symbol: variable AnnualInterestRate location: class Account 3 errors TestAccount.java public class TestAccount { public static void main(String [] args) { //create a new object Identity id = new Identity(100); Balance bal = new Balance(1000); AnnualInterestRate air = new AnnualInterestRate(0.1); //Three variables that retrieve values from the account object's attributes double id = get.id(); double bal = get.bal(); double air = get.air(); double id * bal * air = monthlyinterestrate; } } ERROR: TestAccount.java:15: error: illegal start of expression double id; * bal * air = monthlyinterestrate; ^ 1 error

• Answer:

  You have not declared the variables you are setting in your constructor. It should be like this : public class Account { //attributes double id; double bal; double air; //default constructor public Account() { id = 0.0; bal = 0.0; air = 0.0; } //parameterized constructor (3 parameters) public Account (double id, double bal, double air) { Id = this.id; bal = this.bal; air = this.air; }