Final Keyword Java

final keyword in java in use to restrict the user. we can use final keyword in many context given below:
1. variable
2. method
3. class
variable- A variable can be declare final. If any variable is declare final it can initialize only in constructor.
e.g.
class abc
{
final int a;
abc()
{
a=10;
}
void show()
{
//a=10; - Error
System.out.println("a = "+a);
}

public static void main(String[] args)
{
abc zking =new abc();
zking.show();
}
}

A static final variable can be initialize only in static block.
e.g.
class abc
{
final static int a;
static
{
a=10;
}
void show()
{
//a=10; - Error
System.out.println("a = "+a);
}

public static void main(String[] args)
{
abc zking =new abc();
zking.show();
}
}

A final parameter value can't be change.
e.g.
class zking
{
void show(final int x)
{
//x=10; - error
System.out.println("x = "+x);
}
}
class abc
{
public static void main(String[] snp)
{
xyz obj=new xyz();
obj.show(5);
}
}

A final method can't be override.
e.g.
class zking
{
final void show()
{
System.out.println("Example of final method");
}
}
class abc extends zking
{
//void show() - error
void show1()
{
System.out.println("show can't be override here");
}

public static void main(String[] args)
{
abc obj =new abc();
obj.show();
obj.show1();
}
}

A final class can't be extend.
e.g.
final class zking
{
void show()
{
System.out.println("class can't extends");
}
}
//class abc extends zking  - Error
class abc
{

public static void main(String[] args)
{
zking obj=new zking();
obj.show();
}
}