Every non-static member function has a hidden pointer parameter named this which refers to the instance of the class the function was invoked against. For a given class, C, the type of the hidden this pointer is const C* but if the function is declared const, the pointer is const C* const. When referring to any class member, m, from within any non-static member function, this->m is implied.
Value
Value, and its datatype depends on whatever variable we're changing.
Overloading happens when you have multiple methods in the current class that have the same name but different signature. The scope of method overloading is "Within the current class" Overriding happens when your current class extends another class (the parent class) and provides implementation for a method that is already available in the parent class. The scope of method overriding too is "Within the current class"
if you have a function or a method that takes Object as a parameter, you can call that function or method and pass an Object as follows: Let's say you have a class that extends Object and a function as follows public class A extends Object { ..... } void function ( A arg ){ ..... } To call this function, you need an instance of the class A A objectInstance = new A(); function(objectInstance); The next line shows how to pass an instance of the class A to the function.
All class from package java.lang is implicitly installed.
The String array args refers to the arguments that the program may require before starting. In many cases you may want the program to take some values as input for processing. this string array is for that purpose.
Value, and its datatype depends on whatever variable we're changing.
Final methods are used when a class is inheritable but should have some functions that must not be overridden for them to operate properly. This allows a class that can be inherited, but still have limits on its customization. Usually, final methods are declared so that a method that accepts a parameter of class A can accept a parameter of class B that inherits from A, and the designer of class A can still be certain that the method will operate as intended regardless of what the developer does in class B.
Overloading happens when you have multiple methods in the current class that have the same name but different signature. The scope of method overloading is "Within the current class" Overriding happens when your current class extends another class (the parent class) and provides implementation for a method that is already available in the parent class. The scope of method overriding too is "Within the current class"
if you have a function or a method that takes Object as a parameter, you can call that function or method and pass an Object as follows: Let's say you have a class that extends Object and a function as follows public class A extends Object { ..... } void function ( A arg ){ ..... } To call this function, you need an instance of the class A A objectInstance = new A(); function(objectInstance); The next line shows how to pass an instance of the class A to the function.
All class from package java.lang is implicitly installed.
its a parameter
The String array args refers to the arguments that the program may require before starting. In many cases you may want the program to take some values as input for processing. this string array is for that purpose.
Here is an example program that passes a Scanner object: import java.util.*; public class Conversion { public static void main(String[] args) { Scanner in = new Scanner(System.in); doSomething(in); } public static void doSomething(Scanner in) { int q = in.nextInt(); System.out.println("The value you entered is: " + q); } }
pageThe implicit variable page is of class java.lang.Object and it refers to instance of generated servlet. It is declared asObject page=thisConsider will give ErrorgetServletInfo() is not a method of java.lang.Object is validpageContextpageContext variable is of type javax.servlet.jsp.PageContext. The PageContext class is the abstract class and JSP engine vendor provides its concrete subclass.·Store reference to implicit objects,·Provide method to get and set attributes in different scopes.·Provide convenience methods for transferring request to other resources in web application.PageContext.forward("other.jsp");
In Java, an implicit argument refers to an argument that is not explicitly provided by the programmer when calling a method. These arguments are typically provided by the language or the system environment automatically. Examples include the "this" reference in non-static methods and the default constructor arguments.
Yes. The main method is just like any other java method and can be overloaded. But - Only the method with public static void main(String[] args) signature will get invoked when the class is run.
Yes. Any base class method that is declared virtual can be overridden by a derived class. Overriding a method that is not declared virtual can still be called, but will not be called polymorphically. That is, if you call the base class method, the base class method will execute, not the override. To call a non-virtual override you must call it explicitly.