BRINGING THE PIECES TOGETHER II – Interface Declaration and Implementation

In my last post, we started bringing together the pieces of our previous tutorials together – we were able to set up our IDEs, created packages, classes, variables and Identifiers. In this post, we will continue from where we stopped which was the class. Looking again at the structure of our application (AreaofShapes) as we discussed earlier here, we have three packages, nine (9) classes and one (1) interface altogether as shown below.


In the last lesson, I explained the purpose of each package and we saw the content of ShapeVariableBean and how encapsulation came to play. Today, we will focus more on the package and also, we will see how other classes implements interface within this package. In package, the shapes are divided into two; PolygonController and NonpolygonController.

Note: As an update on the last post, I added a new item on this package which is what we will be focusing on today. I added interface AllShapesInterface above so we can see how to make use of an interface in the course of these set of lessons. Before we continue, please refer to my earlier post on interface where I explained in detail what an Interface is in case you missed the lesson.

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Java Statements

A Java program is made up of classes, these classes are made up of methods, constructors and variable definitions, these methods and constructors are made up of set of instructions and these set of instructions are called statements in Java. Statements are tasks carried out by the computer to solve a problem, they are the building blocks of a Java Program. In order to have a good understanding of Java Statement it will first be beneficial to understand how to break a solution down into algorithmic steps. Each step of an algorithm can be represented as a Java statement or statements.

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