Interview Questions

The wait(), notify(), and notifyAll() methods are used to provide an efficient way for threads to wait for a shared resource. When a thread executes an object's wait() method, it enters the waiting state. It only enters the ready state after another thread invokes the object's notify() or notifyAll() methods..

To create directory on the HD we use mkDir() method:

boolean mkDir();

This method returns true if the directory is created on HD

This method returns false if the directory is already existing on HD

Variable costs are expenses that vary in proportion to the amount of goods or services that a business produces. 

Examples of variable cost include labor, packaging and raw materials.

By asking this the interviewer want to know how much will you obey and obedient to your respective authorities.

Example answer :

Say that you deal with authority as you deal with customers - with integrity, professionalism and politeness.

Applicant should answer that as a first line supervisor, he/she should directly supervise sales workers in a retail department. He/She would get involved in management functions such as purchasing, budgeting, accounting and ensure quality of supply apart from his/her regular supervisor work.

- The Set interface provides methods for accessing the elements of a finite mathematical set

- Sets do not allow duplicate elements

- Contains no methods other than those inherited from Collection

- It adds the restriction that duplicate elements are prohibited

- Two Set objects are equal if they contain the same elements

Use Interfaces when…

- You see that something in your design will change frequently.

- If various implementations only share method signatures then it is better to use Interfaces.

- You need some classes to use some methods which you don't want to be included in the class, then you go for the interface, which makes it easy to just implement and make use of the methods defined in the interface.

Use Abstract Class when…

- If various implementations are of the same kind and use common behavior or status then abstract class is better to use.

- When you want to provide a generalized form of abstraction and leave the implementation task with the inheriting subclass.

- Abstract classes are an excellent way to create planned inheritance hierarchies. They're also a good choice for nonleaf classes in class hierarchies.