Object(instance): basic unit of object-oriented programming and represent real life entities.

Field(optional): primitives or references to object.
1. Also can refer to another object
Method(optional): a class objects can do
1. Declaration part (the signature of the method)
  1. Return value
    1. or primitive
    2. or object
    3. or void: null
  2. Mthod name
  3. list of arguements
2. Body
  1. code that perform the action
3. Main: a special method
  1. Application : many class and only one need main method to be invoked
4. UML diagram: summary of all fields type and methods signature
Class: a blueprint or a template to create objects of identical type.Determine the object(name methods field)
1. ＞=1 Constructor
  1. Like a method, but no return value, the same name with the class. the argument to initialize the field
2. allocate memory space for data that will be assigned to the vairable.
  1. stack :pimitives
  2. heap: JAVA object
Abstraction: the act of using programming object to represent a real-world object
＞=1 reference variable
1. Null: no value .Test by operator

Resource summary

	Created by Zixuan Qiu over 4 years ago