Week 7: Initializing Objects and Classes

•Object - Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors -wagging, barking, eating. An object is an instance of a class.

•Planet p = new Planet();

•Let us now look deep into what are objects. If we consider the real-world we can find many objects around us, Cars, Dogs, Humans, etc. All these objects have a state and behavior.

•If we consider a dog, then its state is - name, breed, color, and the behavior is - barking, wagging, running

•If you compare the software object with a real world object, they have very similar characteristics.

•A class can contain any of the following variable types.

•Local variables: Variables defined inside methods, constructors or blocks are called local variables. The variable will be declared and initialized within the method and the variable will be destroyed when the method has completed.

•Instance variables: Instance variables are variables within a class but outside any method. These variables are instantiated when the class is loaded. Instance variables can be accessed from inside any method, constructor or blocks of that particular class.

•Class variables: Class variables are variables declared with in a class, outside any method, with the static keyword.