Interview Questions

- 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

Yes, we can. In order to compile a java program, we don't require any main method. But to execute a java program we must have a main in it (unless it is an applet or servlet). Because main is the starting point of a java program.

Adb is short for Android Debug Bridge. It allows developers the power to execute remote shell commands. Its basic function is to allow and control communication towards and from the emulator port.

Pass By Reference means the passing the address itself rather than passing the value. Passby Value means passing a copy of the value to be passed.

An abstract class is an incomplete class. An abstract class is defined with the keyword abstract . We cannot create an object of the abstract class because it is not complete. It sets a behavioral protocol for all its child classes.

Before form , After form , Before report, Between page, After report.

The android system will keep all the process that are hosting the services together at one place till the time the service is not started or connected to the client. The priority of the process is divided when running low on memory or when the process has to be killed. The process lifecycle is as follows:
- The service is running currently then the methods onCreate(), onStartCommand(), and onDestroy()methods, will run in the foreground to execute the process without being killed.
- The service is already started then the process can be considered as less important then the processes that are currently visible and used. This is done as there are only few processes that are visible to the users on the screen.
- The clients are bounded to the services they are providing requires more priority in the execution list.
- The service that is started uses startForeground(int, Notification)API to allow all the services to run in the foreground state. The system considers only the services where the user is still active as the services not to be killed.

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.