Technology Questions

- The Dictionary class is an abstract class.

- Classes like Hashtable which map keys to values inherit from this class. 

- An object can be looked for if a dictionary and a key is provided.

- Any non-null object can be used as a key and as a value.

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.

- 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.

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.

Overriding is a method with the same name and arguments as in a parent, whereas overloading is the same method name but different arguments

Microsoft security patches are intended to solve certain security loopholes and problems, while at the same time upgrading any existing security features. This would provide better protection by reducing vulnerabilities in security.

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.