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Java This Keyword

Java This Keyword Example explains step by step details of using java this keyword.

"Java This keyword" is a reference to the current object, it is very helpful when you need to refer an instance of a particular Object from its available methods or using it's constructor, also "this" keyword helps us to avoid naming conflicts.

The following are different ways to use java this keyword

  • 1) Using with instance variable

  • 2) Using with Constructor

  • 3) Pass / Return current instance

Using with instance variable

Using this keyword inside a method or constructor it will use instance variable instead of local variable, in the absence of this keyword it will use local variable

public class ThisExample {

 
public static void main(String[] args) {
   
Student student = new Student("Rockey", 65);
 
}
}


class Student {
 
public int marks;
 
public String name;
 
 
// instance variable is used when creating object
 
public Student(String name, int marks) {
   
this.name = name;
   
this.marks = marks;
 
}
}

Using with Constructor

Using this keyword inside constructor like following

this("Sony", 20);

it will call the constructor having same parameter

 

public class ThisExample {

 
public static void main(String[] args) {
   
Student student = new Student("Rockey", 65, 22);
 
}
}


class Student {
 
public int marks;
 
public String name = "";
 
public int age;

 
// constructor
 
public Student(String name, int marks) {
   
this.name = name;
   
this.marks = marks;
 
}

 
public Student(String name, int marks, int age) {
   
// calls another constructor
   
this("Sony", 20);
 
}
}

Pass / Return current instance

Using this keyword like following

student.calculate(this);

It will pass the current instance to appropriate method

 

 

Using this keyword with return statement like following

return this;

It will returns the current instance

 

public class ThisExample {

 
public static void main(String[] args) {
   
Student student = new Student();
    student.calculate
(66, 22);
 
}
}


class Student {
 
public int marks;
 
public String name = "";
 
public int age;

 
public Student calculate(int marks, int age) {
   
this.marks = marks;
   
this.age = age;
   
return this;
 
}
}



Java This Keyword Example This Keyword In Java How To Use This Keyword In Java What Is This Keyword In Java Usage Of This Keyword In Java

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1 Comments on "Java This Keyword"
27.08.2013 09:52:20 vijay makwana
Very good explanation. :)
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