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access unit comparison table
Subject call is part of destroy in add declare protect is a subtopic of name after access declare by be only accessible to create refer to access by have typically extend implement by has part provide place in represent inherit return to contain have purpose is a synonym of pass as have example instantiate you implement import from have scope be part of belong to order is a kind of overload call when be a descendant of define specify by have access modifier compile by inherit by hide use override have syntax have benefit be a member of be not have have part return has definition be is partitioned into facilitate
class   0 or more methods to the methods it inherits from its superclassa list of variables, called instance variables, corresponding to data that will be present in each instanceits members from access by other classes or objects using an access modifierClassesthe internals of a computer system such as 'Record', 'Table', 'Data', 'Structure', or 'Information'any public class in other packages      only one superclass  implementation for all its instance methods unless the class is abstractits own source fileseveral similar objectsbehaviour from its superclass data associated with each object   
public class HelloWorld {
   public static void main(String[] args) {
      System.out.println("Hello World!");
   }
}
create an instance of itmore than one interfacea package   elements as follows:
  1. class variables
  2. instance variables
  3. constructors
  4. the most important public methods
  5. methods that are simply used to access variables
  6. private methods
specification  Object classa class type whose instances are the values of the class type1 class definition   an implements clause to declare that it contains methods for each of the operations specified by the interfacemethods that are inherited from the class's superclass
class classname
{  // declarations of variables
   // declarations of constructors 
   // declarations of other methods with public ones first
}
1 named package rather than the default package a unique name since somebody in the future might want to import the packages containing both classes and hence create a name clashconstructor A template that describes the data and behaviour of its instances called objectsthe unit of data abstraction in an object-oriented programabstract class, concrete class 
constructorthe zero-parameter constructor in the direct superclass firstclass    Constructors       1 or more arguments that determine some of the values of the variables of the class    a way to initialize a new object     to initialize the instance variables of a newly created object and perform any other needed initialization  
//Example of constructor for the class Stack
public Stack() {
    items = new Vector(10);
}
       access unitusing method name overloadingthe new operator is used to create an instance of a class    a subclass a constructor of the class's superclass with a super() call    a methodthe same name as its class a valueA procedure that is called whenever a new object is created  data abstraction
interface      Interfaces   classes that are defined in the same package unless the interface is public     1 or more interfaces1 or more class many of the same benefits as multiple inheritance  all constants and methods from its superinterfaces abstract methodsabstract data type 
public interface Drawable
{
  public abstract Image drawImage();
  public abstract Image drawImage(int height, int width);
  public abstract Image drawBlackAndWhiteImage(int height, int width);
}
       specification   a set of methods public, or nonethe Java compiler into a .class file    
public interface InterfaceName extends SuperInterfaces
{
    InterfaceBody
}
 1 named package 1 or more superinterfacesinterface definition A named collection of method declarations (without implementations), may also include constant declarations (variables marked static and final)abstract by definition - the modifier is optional in the declaration  
method      Methods all instance variables of all objects of its class  an object by instantiating a class other methods and variables in any class in the same package by default   a block of implementation code    its caller from only one place which should be the last statementreturn statement unless it has a void return type member functionan argument to a method or constructor    a class or an objecta class specification   its return type   instance variables, class variables from other objectsthe super method to invoke a method declared in the superclassa method in a superclass with the same name    a comment at its head if the method is non-obviousmethod signaturea value that is of the return type of the method or a subtype of that typeCode that specifies some of the behaviour of a class or instancepublic except for those that will definitely need to be called from outside the packagestatic method, instance method 
variable  the block where it is declared   Variables and Data Types  giving the data type followed by the name of the variable  a class or an object or a primitive datumother variables and methods in any class in the same package by default    value     only values that are of the same type as the variable or a subtype of the variable's typeto refer to an object or a class or a primitive datum          access unit              comment if it is non-obvious  An item of data named by an identifieras private as possiblemember variable, local variable, formal parameter 

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