This tutorial is explain about Java Keywords likes final keyword, new keyword, static keyword and this keyword with explanation and given example of Java Programming.
Final Keyword:
Final keyword is a non access modifier used for class, attributes and method. If you use final keyword then that value is not changeable. Final keyword is use before of method then method does not override and use before a class then class is not inherited. Final keyword you used when you require that variable always store same value
Declaration Example :-
final int mValue=5;
mValue=7; // its generated error
System.out.println(+mValue);
Static Keyword:
Static is a keyword in java. which is mainly used for a memory allocation. The static keyword is used to share same variable and method for given class. For example in company there have many employees working there ID and Name is different but company name is same then you use static keyword for all the employees.
Most Read:- Inheritance in Java?
class Company{
int mId;
String mEname;
static String mCompanyname="GK InfoTech";
Company( int Id, String name){
mId=Id;
mEname=name;
}
display(){
System.out.println("EmployeeId="+mId,\n "Employee Name="+mEname, \n "Company Name="+mCompanyname);
}
}
class EmployeeMain {
public static void main(String [] args){
Company mCompany1= new Company(1, "Raj");
Company mCompany2= new Company(2, "Rakesh");
mCompany1.display();
mCompany2.display();
}
}
Output:-
EmployeeId= 1
Employee Name= Raj
Company Name= GK InfoTech
EmployeeId= 2
Employee Name= Rakesh
Company Name= GK InfoTech
Most Read:-what is abstraction and used abstract class & method in Java?
new Keyword:-
new keyword is used to create an instance of the class. It is used to allocate a memory for a new objects and returning a reference of that memory.
Test obj = new Test();
this Keyword:-
this keyword is a reference variable that refer to the objects. this can be used to invoke in class, method and constructor.
Problem without use of this Keyword in Class:-
class Company{
int mId;
String mEname;
static String mCompanyname="GK InfoTech";
Company( int mId, String mEName){
mId=Id;
mEname=name;
}
display(){
System.out.println("EmployeeId="+mId,\n "Employee Name="+mEname, \n "Company Name="+mCompanyname);
}
}
class EmployeeMain {
public static void main(String [] args){
Company mCompany1= new Company(1, "Raj");
Company mCompany2= new Company(2, "Rakesh");
mCompany1.display();
mCompany2.display();
}
}
Output:-
EmployeeId= 1
Employee Name= null
Company Name= GK InfoTech
EmployeeId= 2
Employee Name= null
Company Name= GK InfoTech
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Using this Keyword:-
class Company{
int mId;
String mEname;
static String mCompanyname="GK InfoTech";
Company( int mId, String mEName){
this.mId=Id;
this.mEname=name;
}
display(){
System.out.println("EmployeeId="+mId,\n "Employee Name="+mEname, \n "Company Name="+mCompanyname);
}
}
class EmployeeMain {
public static void main(String [] args){
Company mCompany1= new Company(1, "Raj");
Company mCompany2= new Company(2, "Rakesh");
mCompany1.display();
mCompany2.display();
}
}
Output:-
EmployeeId= 1
Employee Name= Raj
Company Name= GK InfoTech
EmployeeId= 2
Employee Name= Rakesh
Company Name= GK InfoTech
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