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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Basic Java Keywords and syntax I

A Syntax is the arrangement of words and phrases to create well-formed sentences in a language. According to Wiki, Java syntax is the set of rules defining how a Java program is written and interpreted. The Syntax is constantly improved in major JDK releases. This lesson will be divided into posts because there is so much to talk about. Please endeavour to look up on the keywords as I’ll be as brief as possible on each syntax.

Package: A package is a name space that mainly contains classes and interfaces. It is a mechanism to encapsulate a related group of classes, interfaces and sub packages providing access protection and name space management.

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