Practice Problems Practice Problems 1. Define a class named Payment that contains an instance variable of type double that stores the amount of the payment and appropriate get and set methods. Also...

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Practice Problems Practice Problems 1. Define a class named Payment that contains an instance variable of type double that stores the amount of the payment and appropriate get and set methods. Also create a method named paymentDetails that outputs an English sentence to describe the amount of the payment. Next, define a class named CashPayment that is derived from Payment. This class should redefine the paymentDetails method to indicate that the payment is in cash and the amount. Include appropriate constructor(s). Define a class named CreaditCardPayment that is derived from Payment. This class should contain instance variables for the name on the card, expiration date, and card number. Include appropriate constructor(s). Finally, redefine the paymentDetails method to include all credit card information and payment amount in the printout. Define a class named DebitCardPayment that is derived from CreditCardPayment. This class should contain an instance variable for the name on the PIN. Include appropriate constructor(s). Finally, redefine the paymentDetails method to include all debit card information and payment amount in the printout. Define a class named PaymentTest class that contains a main method that declares a Payment reference variable, and creates a CashPayment object, a CreditCardPayment object and a DebitCardPayment object with different values. Assign each object to the Payment reference variable and then calls paymentDetails for each until all objects’ paymentDetails are called once. (5 pts) 2. Define a class named Document that contains an instance variable of type String named text that stores any textual content for the document. Create a method named toString that returns the text field and also include a method to set this value. Next, define a class for Email that is derived from Document and includes instance variables for the sender, recipient, and title of an email message. Implement appropriate set and get methods. The body of the email message should be stored in the inherited variable text. Redefine the toString method to concatenate all text fields. Similarly, define a class for File that is derived from Document and includes an instance variable for the pathname. The textual contents of the file should be stored in the inherited variable text. Redefine the toString method to concatenate all text fields. Finally, define a class DocumentTest that creates two objects of each type Email and File in the main method. Test your objects by passing them to the following function that returns true if the object contains the specified keyword in the text property. (5 pts) public static boolean ContainsKeyword(Document docObject, String keyword) { if (docObject.toString().indexOf(keyword,0) >= 0) return true ; return false; }