Technology Questions

Q:

What is the difference between an Interface and an Abstract class ?

Answer

1.Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. A Java abstract class can have instance methods that implements a default behavior.


2.Variables declared in a Java interface is by default final. An abstract class may contain non-final variables.


3.Members of a Java interface are public by default. A Java abstract class can have the usual flavors of class members like private, protected, etc..


4.Java interface should be implemented using keyword “implements”; A Java abstract class should be extended using keyword “extends”.


5.An interface can extend another Java interface only, an abstract class can extend another Java class and implement multiple Java interfaces.


6.A Java class can implement multiple interfaces but it can extend only one abstract class.


7.Interface is absolutely abstract and cannot be instantiated; A Java abstract class also cannot be instantiated, but can be invoked if a main() exists.


8.In comparison with java abstract classes, java interfaces are slow as it requires extra indirection.

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Subject: Java

0 2330
Q:

Why we use array_flip

Answer

array_flip exchange the keys with their associated values in array ie. Keys becomes values and values becomes keys.

<?php
$arrayName    = array("course1"=>"php","course2"=>"html");
$new_array    = array_flip($arrayName);
print_r($new_array);
?>

OUTPUT :

Array
(
[php]     => course1
[html]    => course2
)

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Subject: PHP

0 2329
Q:

What is a TCP Session?

Answer

the layer that establishes ,manages and terminates the session between two communticating devices

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Q:

What is JAR file?

Answer

A JAR file (short for Java Archive) is a ZIP file used to distribute a set of Java classes. It is used to store compiled Java classes and associated metadata that can constitute a program

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Subject: Java

0 2324
Q:

what is the use of virtual destructor in c++?

Answer

A destructor is automatically called when the object is destroyed. A virtual destructor in C++ is used primarily to prevent resource leaks by performing a clean-up of the object.

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Subject: C++

0 2323
Q:

What are instance variables?

Answer Instance variables are those which are defined at the class level. Instance variables need not be initialized before using them as they are automatically initialized to their default values.
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Subject: Java

0 2323
Q:

What is BAS? What is its function ?

Answer

The Business Application Support (BAS) functional area at SLAC provides administrative computing services to the Business Services Division and Human Resources Department. We are responsible for software development and maintenance of the PeopleSoft applications and consultation to customers with their computer-related tasks.


It's called Broadcast Agent Server. Its function is torun the jobs or reports scheduled and can be monitored using Broadcast Agent Console.

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0 2322
Q:

What is the purpose of overriding toString() method?

Answer

we can override tostring() method to return String representation of our object data

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Subject: Java

0 2320