Technology Questions

To use an iterator to traverse through the contents of a collection, follow these steps:

- Obtain an iterator to the start of the collection by calling the collections iterator() method.

- Set up a loop that makes a call to hasNext(). Have the loop iterate as long as hasNext() returns true.

- Within the loop, obtain each element by calling next().

Top level class is also called outer class. It is not defined inside any class.

Ex:

class A {  //top level class

}

Group of tables physically stored together because they share common columns and are often used together is called Cluster.

- Because of the block nature, multiple statements are processed at once thereby improving performance. 

- PL/SQL handles exceptions on catching which, action can be taken. 

- PL/SQL is highly portable as it works with all procedural languages and is highly secured because of privileges.

Constructor is not a special method.

Constructor is block of code that is executed automatically whenever object of the class is created.

- Virtual domain is the domain of the client on which they can run their applications without having to install the server or hardware. 

- The software need not to be installed physically on the server as it can be done using the local repositories and maintaining the domain locally. 

- Using the virtual domain the server storage space is utilized efficiently and the data can be made more secure before publishing it online. 

- Virtual domains are used to represent the personal Internet web address domain name and can be made with your personal one. 

- Virtual domain provides more security in terms of using your own personalized domain and allows the access to the resources that are on web.

For inserting, deleting, and locating elements in a Map, the HashMap offers the best alternative. If, however, you need to traverse the keys in a sorted order, then TreeMap is your better alternative. Depending upon the size of your collection, it may be faster to add elements to a HashMap, then convert the map to a TreeMap for sorted key traversal.

Because any Database will supports only 16 foreign keys in a database table. 

It depends upon the Database limits provided to define the Foreign key constraint, e.g. in Sql Server 2005, the recommended max limit for foreign keys is 253, but you can define more.