IT GALAX Interview Questions with Answers – Part 1

This blog explains about IT GALAX Interview Questions with Answers – Part 1 and is given below : 

Java
1. OOPS

Object Oriented Programming (OOPs) Concept in Java
Object-oriented programming:  OOPs refers to languages that uses objects in programming. Object-oriented programming aims to implement real-world entities like inheritance, hiding, polymorphism etc in programming. The main aim of OOP is to bind together the data and the functions that operate on them so that no other part of the code can access this data except that function.
2. Multithreading in Java
Multithreading in java is a process of executing multiple threads simultaneously.

A thread is a lightweight sub-process, the smallest unit of processing. Multiprocessing and multithreading, both are used to achieve multitasking.

However, we use multithreading than multiprocessing because threads use a shared memory area. They don’t allocate separate memory area so saves memory, and context-switching between the threads takes less time than process.

Java Multithreading is mostly used in games, animation, etc.

Advantages of Java Multithreading
1) It doesn’t block the user because threads are independent and you can perform multiple operations at the same time.

2) You can perform many operations together, so it saves time.

3) Threads are independent, so it doesn’t affect other threads if an exception occurs in a single thread.

3. Exception (catch block is private or public or protected)
Exception Handling in Java
The Exception Handling in Java is one of the powerful mechanism to handle the runtime errors so that normal flow of the application can be maintained.

In Java, an exception is an event that disrupts the normal flow of the program. It is an object which is thrown at runtime.

Exception Handling is a mechanism to handle runtime errors such as ClassNotFoundException, IOException, SQLException, RemoteException, etc.

4. SQL  and Joins
SQL | Join (Inner, Left, Right and Full Joins)
A SQL Join statement is used to combine data or rows from two or more tables based on a common field between them. Different types of Joins are:

INNER JOIN
LEFT JOIN
RIGHT JOIN
FULL JOIN

5. Pvt key
A private key is a tiny bit of code that is paired with a public key to set off algorithms for text encryption and decryption. It is created as part of public key cryptography during asymmetric-key encryption and used to decrypt and transform a message to a readable format. Public and private keys are paired for secure communication, such as email.

A private key is also known as a secret key.
6. Foreign key
A foreign key is a key used to link two tables together. This is sometimes also called as a referencing key.

A Foreign Key is a column or a combination of columns whose values match a Primary Key in a different table.

The relationship between 2 tables matches the Primary Key in one of the tables with a Foreign Key in the second table.

If a table has a primary key defined on any field(s), then you cannot have two records having the same value of that field(s).

7. Jsp
Web based /stand alone
Web Application

The UI is rendered on a client machine, using a specialized client (a.k.a. web browser)
The UI capabilities on the client machine are limited to what the web browser (including plugins) supports. The programmer generally has no ability to implement arbitrary functionality on the client, but rather must work within the capabilities supported by the client.
Business logic and data storage are not on the client machine (generally speaking, there can be limited exceptions). Rather, one or more servers take those architectural roles.
Communication between the client and server occurs using a standardized network communication protocol (HTTP).
Stand Alone Application

The programmer has full control (within the capabilities of the operating system and with support of a broad selection of UI frameworks) over the user interface.
The business logic layer and data layer may reside on the same machine or on a remote server.

References

https://www.geeksforgeeks.org/object-oriented-programming-oops-concept-in-java/

https://www.javatpoint.com/multithreading-in-java

https://www.javatpoint.com/exception-handling-in-java

https://www.geeksforgeeks.org/sql-join-set-1-inner-left-right-and-full-joins/

https://www.techopedia.com/definition/16135/private-key

https://www.tutorialspoint.com/sql/sql-foreign-key.htm

https://stackoverflow.com/questions/7845451/technical-difference-between-a-stand-alone-app-vs-web-app