Interview Questions

The main reason why the scope resolution operator (::) cannot be overloaded is that only operators that take in values as parameters can be overloaded. The scope resolution operator does not take a value as parameter.

new ClassName();

This expression creates object in heap area and returns that obj address. Here JVM creates object but JVM does not returns object original address. JVM returns duplicate address, duplicate address is also called as hashcode. 

The JDBC Driver provides vendor-specific implementations of the abstract classes provided by the JDBC API. This driver is used to connect to the database.

SVG stands for scalable vector graphics. It’s a text based graphic language which draws images using text, lines, dots etc. This makes it lightweight and renders faster.

- A web worker is a JavaScript which runs in the background. It exists in external files. 

 - It is independent of other scripts and does not affect the performance of the page. 

 - Web workers are usually used for CPU intensive tasks.

Six sigma is a data-driven technique and way for eliminating defects in any progress from product to service and from manufacturing to transactional.

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.

There are two major platforms that providing hosting and servers to host on. The differences between them are as follows:

- Unix are more efficient in performing offsite and onsite, whereas windows doesn’t provide very good efficiency to work with. 

- Unix provide lower hosting cost for the website using the high bandwidth, whereas windows take more resources and have the cost higher for the storage. 

- Unix is better for the websites that are static and includes HTML and graphics, whereas Windows is used for heavy websites and having more requirements. 

- Unix supports the scripting languages like PHP and databases like MySQL and other related categories, whereas Windows supports IIS, coldfusion and big applications that take more space.