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Inheritance-2

Limitation of Inheritance:-we know that inheritance is a facility of re-using the previously developed code, but inheritance has some limitation also, that are given below.

1)    Limitation on variables

 private variables are not available to the child class in any ways that means     private variables cannot inherit .

2)    Limitation on functions or methods

Private Fields of super classes are not available to the child class.
3)    Limitation on class

Final classes cannot inherit into child class.

4)    Limitation on Constructor

Inheritance concept is not applicable for constructors, constructors are not inherited.


Example1:-private variables-1


class Account
{
private int balance=100;
 }
class Test extends Account
{
void getBalance()
{
System.out.println("Your balance is"+balance);
}
public static void main(String[]args)
{
Test t=new Test();
t.getBalance();
}
}

Output:-

C:\JAVATECH>javac Test.java

Test.java:13: error: balance has private access in Account
System.out.println("Your balance is"+balance);
                                     ^
1 error


Private variables cannot inherit in child class, but private variables are used by the methods of that class and method can be inherited into child class.


Example2:- private variables-2


class Account
{
private int balance=100;
 void balance()
{
System.out.println("Your balance is"+balance);
}
}
class Test extends Account
{
public static void main(String[]args)
{
Test t=new Test();
t.balance();
}
}

Output:-

C:\JAVATECH>javac Test.java
 C:\JAVATECH>java Test

Your balance is100


Example3:-private function-1


class Account
{
private void balance()
{
System.out.println("Your balance ");
}
}
class Test extends Account
{
public static void main(String[]args)
{
Test t=new Test();
t.balance();
}
}

Output:-

C:\JAVATECH>javac Test.java

Test.java:15: error: cannot find symbol
t.balance();
 ^
  symbol:   method balance()
  location: variable t of type Test
1 error

Example4:-private function-2


class Account
{
private void balance()
{
System.out.println("Your balance ");
}
void disp()
{
System.out.println("Through disp method");
balance();
}
}
class Test extends Account
{
public static void main(String[]args)
{
Test t=new Test();
t.disp();
}
}

Output:-

C:\JAVATECH>javac Test.java
C:\JAVATECH>java Test

Through disp method
Your balance

Example5:-final class Test.java


final class Account
{
}
class Test extends Account
{
}

Output:-

C:\JAVATECH>javac Test.java

Test.java:5: error: cannot inherit from final Account
class Test extends Account
                   ^

1 error

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