Technology Questions

Array is collection of same data type. Array size is fixed, It cannot be expanded.

But ArrayList is a growable collection of objects.ArrayList is a part of Collections Framework and can work with only objects.

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.

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. 

BlackBerry is nothing but a handheld wireless device that is just like a two way pager.

It supports the features like mobile telephone, push e-mail, text messaging, web browsing, internet faxing.

In addition to these, all types of wireless information services and multi-touch interfaces are also included. 

Basically website is an information provider, It provides information globally using internet protocols.

Math object has two constant : Math.PI and Math.E

Math object has following functions:

- Math.abs(val1);

It will give absolute value of val1.

- Math.max(val1,val2);

This fuction will return maximum value from val1 and val2.

- Math.random();

This function will return a random number between 0 and 1.

- Math.floor(val1)

This function will returns decimal value of val1

- Web hosting services provide internet hosting and its services that provide organization to build the websites. 

- The web hosting services also allow the individuals to access the websites through the World Wide Web. 

- Web hosting provides the space to put their content and allow the clients to provide the Internet connectivity. 

- It provides the data center that allows the use of higher space and connectivity properties for the Internet users. 

- It provides tools to allow the website to run on the servers and easily accessible from the outside world using the browser.

ClassName refName = new ClassName();

or

ClassName refName;

refName = new ClassName();