GoConqr has a new look! Let us know what you think.

Sign up free

Flashcards

212Jaba

Shez F English 48 cards

Cards in this deck (48)

  1. 1Whats an Object1 - An abstract thing
  2. 2Whats a class1 - A set of variables and methods that are encapsulated together
  3. 3What is an instanced Variable1 - A set of zero or more variables encapsulated with in a class
    2 - Person lecturer;
  4. 4What is a method1 - A block of code that is encapsulated with in a single class
    2 - Int getName (){return name;}
  5. 5What is an Instance1 - A realization of a class
    2 - Get their own independent copy of all defined variables
    3 - Person joe = New Person();
  6. 6What is a constructor1 - An optional method that is automatically called by the new operator upon instantiation of a class
    2 - They do not have a defined return type
    3 - Class Person{ Person (int anAge_{ age = anAge;}
  7. 7What is an Actual parameter1 - The variable supplied by the caller
    2 - if(joe.olderThan(18)
    3 - 18 is an actual parameter
  8. 8What is a formal parameter1 - Variable used with in the method
    2 - boolean olderThan(int rating)
    3 - Rating is the formal parameter
  9. 9Is Java pass by value or reference1 - Pass by value
  10. 10What is an Object reference1 - Person p = New Person();
    2 - p = pointer to the new object
  11. 11What does the "this" keyword do1 - Returns an object reference to the instance which the current method is executing in
    2 - Public class Person
    int age
    Person(int age){
    this.age = age;
  12. 12What are reference types1 - Are anything related to objects
    2 - References to objects
    3 - It is the referene that you are accessing or modifying
  13. 13What are Value Types1 - It is the data itself that you are accessing or modifying
  14. 14Why do we use Inheritance1 - To promote reuse and extensibility
  15. 15What is Inheritance1 - Where onne class can be derived from or extend another to create a new class
    2 - We use EXTENDS
  16. 16What happens when we use extends1 - The instance variables and methods defined implicitly become part of the new class
    2 - Those variable and methods can be accessed in the new class
  17. 17Example of Inheritance..public class Lecturer extends Person{}
    1 - All methods in the superclass become part of the new subclass
  18. 18What do we mean by Inheritance is Transitive1 - If a class is a subclass of another. IT is also a subclass of that classes parent class.
    2 - Class Mammal
    3 - Person extends Mammal
    4 - Lecturer extends Person
    5 - Lecturer inherits instance variables and methods from Mammal and person
  19. 19Inheritance Hierarchy1 - Can be mapped out using a tree with a Super class at the top.
    2 - Anything extending is branched out to a leaf/node
  20. 20What happens if we go up/down the tree1 - Up the tree is more abstract
    2 - Down the tree is more specialist
  21. 21What is SUPER DUPER LEMON DUPER REPORT ABUSE SYSTEM !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1 - When we extend a class, we can create a new constructor for the new class or we can use the constructor of the super class
    2 - Super allows us to use the constructor from the super class
    3 - MUST BE THE FIRST THING IN CONSTRUCTOR!!!!!!!!!!!!!!!!!!!!!!!!
  22. 22What is method Overriding1 - Used to change the behavior by replacing a method in the superclass
    2 -
  23. 23What is method overloading1- We can have more than one method with the same in the same class, as long it has different params.
  24. 24What is Polymorphism1 - To take many forms
    2 - Provides backward compatitbility of a subclass with any code written for its superclass
    3 - We use method overrloading and overriding for this
  25. 25What is casting1 - Covert between types of object references
    2 - Only if object is the same class or a subclass of the type you are casting to
  26. 26What is an Abstract Class1 - classes which are not instantiated only extended.
  27. 27What is an abstract method1 - Similar to abstract classes
    2 - Used if you know that method is needed.
  28. 28What is an Interface1 - An abstract specification of 0> methods
    2 - Cannot contain instance variables
    3 - Cannot contain method implementation
    4 - Clas can implement any number of interfaces
  29. 29What is protection1 - Not letting people fiddle with my cogsLOL
    2 -
  30. 30What is a public class1 -Class that is available to everyone to see
  31. 31What is a protected class1 - Exposed to the class, package and the subclass
  32. 32What is a private class1 - Cant be seen by anyone other than the stuff inside THAT class.
  33. 33When do we use accessors1 - Getters
    2 - Only use when you want the variable to be visible outside the class
  34. 34When do we use mutators1 - Only if you want the variable to be mutable (change)
  35. 35What is the final keyword1 - A variable that you assign which is immutable. Doesnt change
    2 - Classes which are final can never be sub classed
    3 - Methods with final can never be changed using overriding
  36. 36What are static variables1 - Variables which are unique to that class
    2 - Variable accessible without the need of an instance
  37. 37What are static methods1 - Methods that operate of instances
    2 - Methods operate ob classes and do need the class to be instantiated
  38. 38What are exceptions1 - A set of classes for supporting run time errors
    2 - They are flow control primitives
    3 - If an exception occurs, then it will run the exception handler
  39. 39What is the try catch1 - Try surronds a block of code which may cause the exception
    2 - Catch defines the code that is executed when the exception is raised
  40. 40What is the finally keyword1 - Surronds the code that you want unconditionally executed after the try catch blocks no matter what
    2 -
  41. 41What is the Throw keyword1 - Where it throw an exception after it has been created
    2 - Is followed by an instance of the exception
    3 - Cannot throw multiple throw
  42. 42What is the throws keyword1 - When you want to declare an exception
    2 - throw after the method or class declaration.
    3 - Can have multiple exceptions declared
  43. 43What are Generics1 - To deal with type-safe objects
    2 - Used when creating a specific instance of that item
  44. 44What are Wildcard Types1 - Represents a wild card types
    2 - = any type
    3 - - float, int, double etc
  45. 45Benefits and drawbacks of generics1 - Extensibility with type safety (+Ve)
    2 - Runtime type erasure. purely compile time (-Ve)
  46. 46What is a collection in Jaba1 - Used to store and manipulate a group of objects
  47. 47What are Iterators1 - Needing to interate over the contens
  48. 48What is a class factory1 - That you expect future class to be polymorphically compatible with
    2 -

Information

Description
Flashcards on 212Jaba, created by Shez F on 16/05/2017.
Created by
Shez F
Views
5
Rating

Feedback

What is it about?

What do you think of the new look?

How do you like it?