Object and Variables

All data are accessed by means of variables or attributes.
Local variables such as those declared within methods, reside on the runtime stack; space is allocated for them when the method is called and deallocated when a method returns.

Every variable has to be declared and indicates its type.
Primitive types? int, boolean, char. Eg?
Other object types? defined by others. Eg: String and array contains references to objects
Primitive types

Discuss example… int i = 6;
? Other object types(including arrays, String)
Contain references to objects
Created by the use of new operator
E.g.: int [ ] a = new int [3]; array type contain three integer elements
Space for a new array of int object will be allocated on the heap and a reference to the object will be stored in a [i.e. in a stack memory].
Local Variables :
Must be initialized when they are declared. Such as : int =6;
Declaration: indicating type of a variable.
A Java method is a collection of statements that are grouped together to perform an operation. When you call the System.out.println method, for example, the system actually executes several statements in order to display a message on the console.
Now you will learn how to create your own methods with or without return values, invoke a method with or without parameters, overload methods using the same names, and apply method abstraction in the program design.