Technology Questions

The garbage collector assumes that all objects in the managed heap are garbage. It starts walking the roots and builds a graph of all objects reachable from the roots recursively. It stops when it attempts to add an object to the graph that it previously added. The graph contains the set of all objects that are reachable from the application's roots. Any object/s that is not in the graph is not accessible by the application, and is considered garbage. Collection only occurs when the heap is full. In such a case, each and every garbage object calls the Finalize method and reclaims the unused memory

Anonymous class is class without name.

EX:

class A {

}

class Demo {

    A r = new A() {

        }; //anonymous class

}

A NSArray’s contents can not be modified once it’s been created whereas a NSMutableArray can be modified as needed, i.e items can be added/removed from it.

The number of rows returned by a select query can be restricted by the LIMIT clause.
Example:
SELECT * from employee
LIMIT 20

- Cloud architecture uses simple APIs to provide easily accessible services to the user through the internet medium. 

- It provides scale on demand feature to increase the industrial strength. 

- It provides the transparency between the machines so that users don’t have to worry about their data. Users can just perform the functionality without even knowing the complex logics implemented in cloud architecture.

- It provides highest optimization and utilization in the cloud platform

The main types of system calls are as follows:

Process Control: These types of system calls are used to control the processes. Some examples are end, abort, load, execute, create process, terminate process etc.

File Management: These types of system calls are used to manage files. Some examples are Create file, delete file, open, close, read, write etc.

Device Management: These types of system calls are used to manage devices. Some examples are Request device, release device, read, write, get device attributes etc.

Information Maintenance: These types of system calls are used to set system data and get process information. Some examples are time, OS parameters, id, time used etc.

Communications: These types of system calls are used to establish a connection. Some examples are send message, received messages, terminate etc

A unique constraint on a column uniquely identifies the record by a combination of one or more fields. Few unique constraint fields can have a NULL value as long as the combination of values is unique.

Example:
create table employee ( id number NOT NULL, dob DATE, professor_id NOT NULL, Name varchar(200) Constraint id_unique UNIQUE(id,dob) );

By using method.

The method used to get the data is called getter method.