We can use super () as well this () only once inside constructor. If we use super () twice or this () twice or super () followed by this () or this () followed by super (), then immediately we get compile time error i.e, we can use either super () or this () as first statement inside constructor and not both.
What is the difference between this and Super in Java?
this: this is the reserved keyword in Java that is used to invoke constructor, methods, static members of the current class. super: super is the reserved keyword in Java that is used to invoke constructor, methods of the parent class. This is possible only when one class inherits another class (child class extends parent class).
What is the use of Super () method in Java?
super can be used to invoke immediate parent class method. super () can be used to invoke immediate parent class constructor. 1) super is used to refer immediate parent class instance variable. We can use super keyword to access the data member or field of parent class.
Can you use both this () and Super () in a constructor in Java?
Can you use both this () and super () in a constructor in Java? No, you cannot have both this () and super () in a single constructor.
Why can't we use this() and Super() together?
Because this () and super () must be the first executable statement. If you write this () first than super () will become the second statement and vice-versa. That's why we can't use this () and super () together. this () and super (), both are the constructors that's why must be the first statement.
Can super and this be used together in same method?
We can use super() as well this() only once inside constructor. If we use super() twice or this() twice or super() followed by this() or this() followed by super(), then immediately we get compile time error i.e, we can use either super() or this() as first statement inside constructor and not both.
What would be the Behaviour If this () and super () together used in a method?
What would be the behaviour if this() and super() used in a method? Explanation: this() and super() cannot be used in a method. This throws compile time error.
How are this () and super () used with constructors?
super() acts as immediate parent class constructor and should be first line in child class constructor. this() acts as current class constructor and can be used in parametrized constructors. When invoking a superclass version of an overridden method the super keyword is used.
Why we Cannot use this and super in static method?
Where the "super" keyword in Java is used as a reference to the object of the superclass. This implies that to use "super" the method should be invoked by an object, which static methods are not. Therefore, you cannot use the "super" keyword from a static method.
What is the output of this () and super () is used in the method?
this keyword used to call default constructor of the same class. super keyword used to call default constructor of the parent class. this keyword used to access methods of the current class as it has reference of current class. One can access the method of parent class with the help of super keyword.
Can we use both this () and super () in the same constructor?
“this()” and “super()” cannot be used inside the same constructor, as both cannot be executed at once (both cannot be the first statement).
Can we use this and super in same constructor?
No, you cannot have both this() and super() in a single constructor.
Which statements are true about super () or this ()?
0 super keyword is used to invoke immediate parent class method All the given options are correct super() is used to invoke immediate parent class constructor .
What would be the Behaviour If this () and super () used in a method OA runtime error OB throws exception OC compile time error OD runs successfully?
1 Answer. The explanation: this() and super() cannot be used in a method. This throws compile time error.
What would be Behaviour if the constructor has a return type?
Answer: The constructor cannot have a return type. It should create and return new objects. Hence it would give a compilation error. ...
Which of these can be used to differentiate two or more methods having the same name?
Correct Option: D Return type of method, Number of parameters and Parameters data type can be used to differentiate two or more methods having same name.
Which of these methods is used to write () into a file?
Which of these methods is used to write() into a file? Explanation: None.
Abstract
The this and super are reserved keywords in Java.
Scope of the Article
The article will explain this and super keyword used in Java Programming.
Introduction
Java provides many implicit keywords among those “ this ” and “ super ” are two reference variables. “ this ” and “ super ” are used to resemble the reference variable pointing to sub-class or parent class (superclass).
What is this keyword in Java?
Let us under the use of this keyword using the above code snippet. As we can see that we have a variable 'var' and a parameter 'var' inside the method function. If we want to assign the value of parameter 'var' to the variable 'var' inside the class then we have to use the this keyword.
Difference Between this and super Keyword in Java
1. "this" is an implicit reference variable keyword used to represent the current class.
Can we Use Both this () and super () in the Same Constructor?
No, we cannot use the “ this () ” and “ super () ” in the same constructor. If we want to use “ this () ” or “ super () ” inside a constructor, they must be written (executed) at first. Both “ this () ” and “ super ” cannot be executed simultaneously, hence “ this () ” and “ super () ” in Java cannot be used in the same constructor.
What happens after the parent constructor completes?
After that when Parent () constructor completes then flow again comes back to that No argument constructor of Base class and executes next SOP statement i.e, Base class’s No argument constructor.
What does "no argument" mean in a parent class?
Inside that we have super () which calls the no argument of Parent class since we have written super () and no arguments that’s why it calls no argument constructor of Parent class, in that we have an SOP statement and hence it prints Parent class’s No arg constructor.
What happens when you have a new base in the main?
Inside main we have new Base () then flow goes to No argument constructor of Base class.
What is super used for in Java?
Similar article : super and this keyword#N#super () as well as this () both are used to make constructor calls. super () is used to call Base class’s constructor (i.e, Parent’s class) while this () is used to call current class’s constructor.
What is the first statement in a constructor?
It can be used only inside constructor and nowhere else. this () is use to refer only current class’s constructor.
Does the no argument constructor of child class flow come back to main?
Further after completing the no argument constructor of child class flow now came back again to main and executes remaining statements and prints Inside Main.
Does flow come back from parent class?
Now as the No argument const of Parent class completes so flow comes back to the no argument of the Child class and in that we have an SOP statement and hence it prints Flow comes back from Parent class no arg const.
What is the third private constructor in SecondChild?
In class SecondChild there is introduced third private constructor that takes 2 parameters – first one passed to supper () and the second one used to set name. First 2 constructors are calling the third one. Super () is called exactly once, also instance variable is set only in one constructor. Code produces the same result without need to call super () and this () in same constructor.
What happens when you call a constructor in a method?
As constructor call must be the first statement in the method, so if we define this and super constructor both in a method, then it will become conflict as below. Suppose this constructor is called first then it will check the current class constructor and if in current class constructor we have another method call or statement. So in this call all the methods and statement inside the current class constructor will be called before calling the super class constructor and then it will deny the statement "constructor call must be the first statement in the method"
What is this () used for?
this () is used to call default constructor of same class.it should be first statement inside constructor.
What is the meaning of "back up"?
Making statements based on opinion; back them up with references or personal experience.
Is a constructor call the first statement?
Constructor call must always be the first statement . So you either have super () or this () as first statement. Both this () and super () are constructor calls, and constructor call must be the first (and only first) call in a constructor.
Can you call a super constructor twice?
Thus if both were allowed you could end up calling the super constructor twice.
Can super and super be used together?
1. both this () and super () can not be used together in constructor. this () is used to call default constructor of same class.it should be first statement inside constructor. super () is used to call default constructor of base class.it should be first statement inside constructor.
What is super in Java?
super can be used to refer immediate parent class instance variable. super can be used to invoke immediate parent class method. super () can be used to invoke immediate parent class constructor.
When to use super keyword?
The super keyword can also be used to invoke parent class method. It should be used if subclass contains the same method as parent class. In other words, it is used if method is overridden.
Does the compiler automatically add super to the first statement?
As we know well that default constructor is provided by compiler automatically if there is no constructor. But, it also adds super () as the first statement.
Do animal and dog have a common color?
In the above example, Animal and Dog both classes have a common property color. If we print color property, it will print the color of current class by default. To access the parent property, we need to use super keyword.
