4. Interfaces (13. Object-oriented programming)

Код ChasePaymentProcessor: https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/oop/interfaces/ChasePaymentProcessor.java Код Client class: https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/oop/interfaces/Client.java Код PaymentData: https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/oop/interfaces/PaymentData.java Код PaymentProcessor interface: https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/oop/interfaces/PaymentProcessor.java Код PaymentValidator: https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/oop/interfaces/PaymentValidator.java Код PayPalPaymentProcessor: https://github.com/AndriiPiatakha/learnit_java_core/blob/master/src/com/itbulls/learnit/javacore/oop/interfaces/PayPalPaymentProcessor.java