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Difference between super() and this() in java Program
Along with various other keywords Java also provides this and super as special keywords which primarily used to represent current instance of a class and it's super class respectively. With this similarity both these keywords have significant differences between them which are listed as below -
| Sr. No. | Key | this | super |
|---|---|---|---|
| 1 | Represent and Reference | this keyword mainly represents the current instance of a class. | On other hand super keyword represents the current instance of a parent class. |
| 2 | Interaction with class constructor | this keyword used to call default constructor of the same class. | super keyword used to call default constructor of the parent class. |
| 3 | Method accessibility | 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. |
| 4 | Static context | this keyword can be referred from static context i.e can be invoked from static instance. For instance we can write System.out.println(this.x) which will print value of x without any compilation or runtime error. | On other hand super keyword can't be referred from static context i.e can't be invoked from static instance. For instance we cannot write System.out.println(super.x) this will leads to compile time error. |
Example of this vs. super
Equals.jsp
class A {
public int x, y;
public A(int x, int y) {
this.x = x;
this.y = y;
}
}
class B extends A {
public int x, y;
public B() {
this(0, 0);
}
public B(int x, int y) {
super(x + 1, y + 1);// calls parent class constructor
this.x = x;
this.y = y;
}
public void print() {
System.out.println("Base class : {" + x + ", " + y + "}");
System.out.println("Super class : {" + super.x + ", " + super.y + "}");
}
}
class Point {
public static void main(String[] args) {
B obj = new B();
obj.print();
obj = new B(1, 2);
obj.print();
}
}Output
Base class : {0, 0}
Super class : {1, 1}
Base class : {1, 2}
Super class : {2, 3}
Updated on: 25-Feb-2020
9K+ Views
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