Final Keyword

/* All members and variables can be overriden by default in subclasses. Final Keyword Is Used in Java to prevent the subclass from overridding the members of the superclass. Making a method final ensures that the functionality defiened in the mathod will never be altered in any way. Similarily the value of the final variable can never be altered in any way. */
class fe
{
double fp;
int fr;

fe(double p1,int r1)
{
fp=p1;
fr=r1;
}
}

class se extends fe
{
double sp;
int sr;

se(double p1,int r1,double p2,int r2)
{
super(p1,r1);
sp=p2;
sr=r2;
}
}

final class te extends se
{
double tp;
int tr;

te(double p1,int r1,double p2,int r2,double p3,int r3)
{
super(p1,r1,p2,r2);
tp=p3;
tr=r3;
}

double average()
{
return (fp+sp+tp)/3;
}
}

class Student
{
public static void main(String args[])
{
te student = new te(75.6,40,78.6,44,70.5,48);
System.out.println("Year\tRoll no.\tPercentage");
System.out.println("FE\t"+student.fr+"\t\t"+student.fp);
System.out.println("SE\t"+student.sr+"\t\t"+student.sp);
System.out.println("TE\t"+student.tr+"\t\t"+student.tp);
System.out.println("Average performance is " + student.average());
}
}
/* Output *

Year Roll no. Percentage
FE 40 75.6
SE 44 78.6
TE 48 70.5
Average performance is 74.89999999999999 */