specification Comparison Table

specification

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specification comparison table

Subject have syntax rule add declare protect is a subtopic of name after access be only accessible to create access by 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 be part of belong to specify how order be a descendant of define specify by have access modifier compile by hide use override have syntax have benefit be a member of have have part return has definition be is partitioned into abbreviate as

Application Programming Interface How Java Works a programmer accesses the behaviour and state of classes and objects The specification of how a programmer writing an application accesses the behaviour and state of classes and objects API

class
bold = mandatory
italic = non-terminal
normal font = optional
0 or more methods to the methods it inherits from its superclass a list of variables, called instance variables, corresponding to data that will be present in each instance its members from access by other classes or objects using an access modifier Classes the internals of a computer system such as 'Record', 'Table', 'Data', 'Structure', or 'Information' any public class in other packages
if a class is not declared public
then it is accessible only to members of the same package
only one superclass implementation for all its instance methods unless the class is abstract its own source file several similar objects behaviour 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 it more than one interface a package elements as follows:
class variables
instance variables
constructors
the most important public methods
methods that are simply used to access variables
private methods
Object class a class type whose instances are the values of the class type 1 class definition
public
or private
or protected
an implements clause to declare that it contains methods for each of the operations specified by the interface methods that are inherited from the class's superclass
class classname
{ // declarations of variables
// declarations of constructors
// declarations of other methods with public ones first
}
reusability
modularity
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 clash constructor A template that describes the data and behaviour of its instances called objects the unit of data abstraction in an object-oriented program abstract class, concrete class

interface
bold = mandatory
italic = non-terminal
normal font = optional
Interfaces classes that are defined in the same package unless the interface is public 1 or more interfaces 1 or more class many of the same benefits as multiple inheritance all constants and methods from its superinterfaces
unless the interface hides a constant with the same name
or the interface redeclares a method with a new method declaration
abstract methods
to capture similarities between unrelated classes without artificially forcing a class relationship
to declare methods that one or more classes are expected to implement
to let you define a protocol of behaviour that can be implemented by any class anywhere in the class hierarchy
to reveal an object's programming interface without revealing its class
abstract 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);
}
a set of methods public, or none the Java compiler into a .class file
public interface InterfaceName extends SuperInterfaces
{
InterfaceBody
}
1 named package 1 or more superinterfaces interface 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
bold = mandatory
italic = non-terminal
normal font = optional
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
when a method is called
and the method's parameter is a primitive type
then the memory allocated for that parameter holds a copy of the parameter itself
a block of implementation code its caller from only one place which should be the last statement return statement unless it has a void return type member function an argument to a method or constructor
the behaviour of an object
or the behaviour of a class
a class or an object a class its return type
public
or private
or protected
instance variables, class variables from other objects the super method to invoke a method declared in the superclass a method in a superclass with the same name a comment at its head if the method is non-obvious method signature a value that is of the return type of the method or a subtype of that type Code that specifies some of the behaviour of a class or instance public except for those that will definitely need to be called from outside the package static method, instance method

virtual machine How Java Works just-in-time compilation An abstract specification for a computing device that can be implemented in different ways, in software or hardware VM

Next kbTop: state Up: kbTop Previous kbTop: scope

Subject	have syntax rule	add	declare	protect	is a subtopic of	name after	access	be only accessible to	create	access by		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	be part of	belong to	specify how	order	be a descendant of	define	specify by	have access modifier	compile by	hide	use	override	have syntax	have benefit	be a member of	have	have part	return	has definition	be	is partitioned into	abbreviate as
Application Programming Interface					How Java Works																									a programmer accesses the behaviour and state of classes and objects																The specification of how a programmer writing an application accesses the behaviour and state of classes and objects			API
class	bold = mandatory italic = non-terminal normal font = optional	0 or more methods to the methods it inherits from its superclass	a list of variables, called instance variables, corresponding to data that will be present in each instance	its members from access by other classes or objects using an access modifier	Classes	the internals of a computer system such as 'Record', 'Table', 'Data', 'Structure', or 'Information'	any public class in other packages				if a class is not declared public then it is accessible only to members of the same package	only one superclass			implementation for all its instance methods unless the class is abstract	its own source file	several similar objects	behaviour 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 it	more than one interface	a package				elements as follows: class variables instance variables constructors the most important public methods methods that are simply used to access variables private methods	Object class	a class type whose instances are the values of the class type	1 class definition	public or private or protected			an implements clause to declare that it contains methods for each of the operations specified by the interface	methods that are inherited from the class's superclass	class classname { // declarations of variables // declarations of constructors // declarations of other methods with public ones first }	reusability modularity	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 clash	constructor		A template that describes the data and behaviour of its instances called objects	the unit of data abstraction in an object-oriented program	abstract class, concrete class
interface	bold = mandatory italic = non-terminal normal font = optional				Interfaces			classes that are defined in the same package unless the interface is public				1 or more interfaces	1 or more class		many of the same benefits as multiple inheritance			all constants and methods from its superinterfaces unless the interface hides a constant with the same name or the interface redeclares a method with a new method declaration		abstract methods	to capture similarities between unrelated classes without artificially forcing a class relationship to declare methods that one or more classes are expected to implement to let you define a protocol of behaviour that can be implemented by any class anywhere in the class hierarchy to reveal an object's programming interface without revealing its class	abstract 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); }									a set of methods		public, or none	the Java compiler into a .class file				public interface InterfaceName extends SuperInterfaces { InterfaceBody }		1 named package	1 or more superinterfaces	interface 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	bold = mandatory italic = non-terminal normal font = optional				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	when a method is called and the method's parameter is a primitive type then the memory allocated for that parameter holds a copy of the parameter itself			a block of implementation code					its caller from only one place which should be the last statement	return statement unless it has a void return type		member function	an argument to a method or constructor			the behaviour of an object or the behaviour of a class		a class or an object	a class				its return type		public or private or protected		instance variables, class variables from other objects	the super method to invoke a method declared in the superclass	a method in a superclass with the same name				a comment at its head if the method is non-obvious	method signature	a value that is of the return type of the method or a subtype of that type	Code that specifies some of the behaviour of a class or instance	public except for those that will definitely need to be called from outside the package	static method, instance method
virtual machine					How Java Works																																	just-in-time compilation								An abstract specification for a computing device that can be implemented in different ways, in software or hardware			VM