- When designing an object-oriented,…contract-based programming architecture,…you can frequently choose…between using interfaces and abstract classes.…An abstract class is abstract…because you add the abstract keyword…and then it can contain a mixture…of fully implemented methods and abstract methods.…An abstract method is just like a method in an interface.…It doesn't have an implementation.…It just indicates the method signature…and then any subclasses of an abstract method…must implement that method.…
In this project, the Olive class…is the superclass for two subclasses,…Ligurian and Kalamata.…I'm going to change this class and make it abstract…by adding the abstract keyword after public…and before the keyword class.…Now that doesn't change any behavior on its own.…I'll run the application…and show that everything still works.…But now, I'll declare an abstract method…as part of this class.…I'll place this new method down here…after all the setters and getters,…but before toString.…
I'll set it as public…and then put in the keyword abstract.…
Author
Updated
9/30/2020Released
7/24/2015- Understanding the history and principles of Java
- Installing Java, IntelliJ IDEA, and BlueJ
- Creating a Java project
- Working with variables, values, and expressions
- Working with object data types
- Building, comparing, and parsing strings
- Debugging and exception handling
- Creating loops and reusable code
- Passing arguments by reference or value
- Using simple and complex arrays
- Creating custom classes
- Understanding inheritance and polymorphism
- Managing files with Java libraries
- Documenting code with Javadoc
- Packaging classes in JAR files
Skill Level Beginner
Duration
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Video: Using abstract classes and methods