Project "picture" Authors: Michael Kolling and David J. Barnes This project is part of the material for the book Objects First with Java - A Practical Introduction using BlueJ David J. Barnes and Michael Kolling Pearson Education, 2002 It is discussed in chapter 1. This is a very simple project to demonstrate some characteristics of objects. You can create various shapes, and you will see, if you do, that those shapes are drawn on screen (in a window that we call the "canvas"). You can then manipulate these objects: change their position, size and colour. Try it out: create a few different squares, triangles and circles. This project is designed as a first example of object-oriented programming. It illustrates a number of concepts: - a Java project (application) is a collection of classes - objects can be created from classes - from any one class, many objects may be created - objects have operations (methods) - operations can have parameters - parameters have types (at least String and int) - objects hold data (fields) - the operations and fields are common to all objects - the values stored in the fields can be different for each object The project also demonstrates - BlueJ object creation - interactive method invocation - parameter passing A good second project to look at after this is "picture", which adds a class to those ones in this project. That class (named "Picture") uses the shapes to draw a picture. It can be used to experiment with coding. Michael Kölling, July 2000