Answers for "super keyword in java"

3

new keyword in js

ObjMaker = function() {this.a = 'first';};
// ObjMaker is just a function, there's nothing special about it that makes 
// it a constructor.

ObjMaker.prototype.b = 'second';
// like all functions, ObjMaker has an accessible prototype property that 
// we can alter. I just added a property called 'b' to it. Like 
// all objects, ObjMaker also has an inaccessible [[prototype]] property
// that we can't do anything with

obj1 = new ObjMaker();
// 3 things just happened.
// A new, empty object was created called obj1.  At first obj1 was the same
// as {}. The [[prototype]] property of obj1 was then set to the current
// object value of the ObjMaker.prototype (if ObjMaker.prototype is later
// assigned a new object value, obj1's [[prototype]] will not change, but you
// can alter the properties of ObjMaker.prototype to add to both the
// prototype and [[prototype]]). The ObjMaker function was executed, with
// obj1 in place of this... so obj1.a was set to 'first'.

obj1.a;
// returns 'first'
obj1.b;
// obj1 doesn't have a property called 'b', so JavaScript checks 
// its [[prototype]]. Its [[prototype]] is the same as ObjMaker.prototype
// ObjMaker.prototype has a property called 'b' with value 'second'
// returns 'second'
Posted by: Guest on May-22-2020
8

super keyword in java

Variables and methods of super class can
be overridden in subclass. 
In case of overriding , a subclass
object call its own variables and methods.
Subclass cannot  access the variables and
methods of superclass because the overridden
variables or methods hides the 
methods and variables of super class.
But still java provides a way to access 
super class members even if 
its members are overridden. Super is
used to access superclass variables, methods, constructors.
Super can be used in two forms :
1) First form is for calling super class constructor.
2) Second one is to call super class variables,methods.
Super if present must be the first statement.
Posted by: Guest on January-05-2021
1

new keyword in js

**Important Points** 

1.It creates a new object. The type of this object is object.
2.It sets this new object's internal, inaccessible, [[prototype]] (i.e. __proto__) property to be the constructor function's external, accessible, prototype object (every function object automatically has a prototype property).
3.It makes the this variable point to the newly created object.
4.It executes the constructor function, using the newly created object whenever this is mentioned.
5.It returns the newly created object, unless the constructor function returns a non-null object reference. In this case, that object reference is returned instead.
Note: constructor function refers to the function after the new keyword, as in

new ConstructorFunction(arg1, arg2)
Posted by: Guest on May-22-2020
2

what is super keyword

Variables and methods of super class can be overridden in subclass. 
In case of overriding , a subclass
object call its own variables and methods. Subclass cannot 
access the variables and methods of
superclass because the overridden variables or methods hides the 
methods and variables of super class.
But still java provides a way to access super class members even if 
its members are overridden. Super is
used to access superclass variables, methods, constructors.
Super can be used in two forms :
1) First form is for calling super class constructor.
2) Second one is to call super class variables,methods.
Super if present must be the first statement.
Posted by: Guest on November-30-2020

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