ITCC 121

• Array


  Used to store a collection of data
• Array


  Collection of variables of the same type
• Array


  Stores multiple data items of the same data type
• Types of Array


  • Multidimensional array
  • Single Dimensional array
• 2D array


  • Has two pairs of square brackets
• Array Length


  The length field of an array returns the size of the array
• Object-oriented


  Built on the foundation laid by structured programming concepts
• Components of a method

  • Access Modifier
  • Return type
  • Method Name
  • Parameter list
  • Exception list
  • Method body
• Access Modifiers in Java

  • Default
  • Private
  • Protected
  • Public
• Constructor in Java


  A special method used to initialize objects
• Types Of Constructor


  • Default Constructor
  • Parameterized Constructor - it accepts a specific number of parameters
• this keyword in Java

  Represents the current instance of a class
• Java package


  A group of similar types of classes, interfaces, and sub-packages
• Advantages of Java Package

  • Java package is used to categorize the classes and interfaces so that they can be easily maintained
  • Java package provide access protection
  • Java package removes naming collision
• Built-in Packages


  • java.lang: contains language support classes
  • Java.io: contains classes for supporting input/output operations
  • Java.util: contains utility classes which implement data structures like linked list, dictionary and support for date/time operations
  • java.applet: contains classes for creating Applets
  • java.awt: contain classes for implementing the components for graphical user interface
  • java.net: contains classes for supporting networking operations
• Static import


  Feature introduced in Java programming language that allows members (files and methods) defined in a class as public static to be used in java code without specifying the class in which the field is defined
• Encapsulation


  Defined as the wrapping up of data under a single unit
• Advantages of Encapsulation


  • Data hiding
  • Increased flexibility reusability
  • Testing code is easy
• Get and Set


  • The get method returns the value of the variable name
  • The set method takes a parameter (newName) and assigns it to the name variable. This keyword is used to refer to the current object. However, as the name variable is declared as private, we cannot access it from outside this class
• Java Inheritance


  Means creating new classes based on existing ones. A class that inherits from another class can reuse the methods and fields of that class
• Types of Inheritance


  • Single Inheritance: subclasses inherit the features of one superclass
  • Multilevel Inheritance: a class is extended to another class and extended to another class
  • Hierarchical Inheritance: in which the same class is inherited by more than one class