Interview Questions

"==" checks equality only,
"===" checks for equality as well as the type.

Dynamic binding is orthogonal to dynamic linking. Binding refers to the linking of a procedure call to the code to be executed in response to the call. Dynamic binding It is associated with polymorphism and inheritance, it(also known as late binding) means that the code associated with a given procedure call is not known until the time of the call at run-time.

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.

abstract method is a method declared with abstract modifier but  with out body.

If we print any object by using println() or print() methods.

The println() or print() methods internally calls tostring() method and prints the return value of toString() method.

A Manifest file is a simple text file that tells the browser what to cache and what not to cache. 

There are three sections of a Manifest file:

i.) CACHE MANIFEST - Files listed here are cached after they are downloaded for the first time. 

ii.) NETWORK - Files listed here require a connection to the server, and are never cached

iii.) FALLBACK - Files listed here specify fallback pages if a page is inaccessible

JDBC technology is an API (included in both J2SE and J2EE releases) that provides cross-DBMS connectivity to a wide range of SQL databases and access to other tabular data sources, such as spreadsheets or flat files. With a JDBC technology-enabled driver, you can connect all corporate data even in a heterogeneous environment.

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.