CLASSES AND METHODS

• ·       The ___keyword denotes that the method is not used to return a value.

  VOID
• ·       Parameter is the list of variables in a method declaration while argument is the actual value that is passed when the method is invoked.
• The data type of the return value must match the declared return type.
• Instance variables are variables declared outside the method, constructor, or any block.
• ·       A method is a collection of statements that are grouped together to perform an operation.
• ·       The this keyword represents the object’s name receiving the method call within a method definition.
• Local variables are variables declared within a method definition.
• ·       These variables are only visible to the methods in which they are declared. They are not accessible from the rest of the class.

  LOCAL VARIABLES
• ·       is the mechanism for restricting access to some of the object’s components.

  INFORMATION HIDING
• ·       If an instance variable is public, there are no restriction on where you can use its name.
• ·       If an instance variable is private, its name cannot be used to access it outside of the class definition.
• ·       If the method is public, you can invoke it anywhere without restriction.
• ·       If a method definition is private, the method cannot be invoked within the definitions of methods in its class.
• ·       The accessor is a public method that returns data from a private instance variable
• ·       The mutator is a public method that changes the data stored in one (1) or more private instance variables.
•   It is the process of combining data and actions into a single item.

  ENCAPSULATION
• o   It groups instance variables and methods into a class.

  ENCAPSULATION
• o   It hides implementation details.

  ENCAPSULATION
• describes the structure of a class by displaying the class name (first row), variables (second row), and methods (third row).

  uml class diagram
• A variable of a class type contains the memory address of the object named by the variable.
• ·       The address of the object’s memory location is called a reference to the object.
• ·       Class types are reference types whose variables hold references or memory addresses.
• ·       Instead of using == for comparison, use the equals() method.