Java Questions

When ever two or more threads are sharing same data for updating then unpredicted result will be there in the data.

For Example take a thread is depositing amount in Account Object and another thread is withdrawing amount from the same Account Object.

when ever both threads are executed simultaneously then unexpected result is stored in the balance of the  Account Object. 

A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator. We cannot invoke a constructor directly.

A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator.

Client code must use setters and getters to access internal data in DataHiding

Whenever there is local- variable/parameter inside the method with same name as data member.

Ex:

Class Sample {

 int a;

  void show() {

   int a=5;

   system.out.println(a); // 5

   system.out.println(this.a);//23

  }

}

class MainApp {

  Public static void main(String[] args) {

  Sample s = new Sample();

   s.a = 23;

   s.show();

   }

}

we can override tostring() method to return String representation of our object data

Wrapping is also called as packing or boxing.

Storing the data inside the object as private data which can accessed outside the class only by using methods.