Persistent Systems Interview Questions and Answers for Freshers

DNS (Domain Name System) translates domain names to IP addresses, while DHCP (Dynamic Host Configuration Protocol) assigns IP addresses to devices.

• DNS resolves human-readable domain names (e.g., www.example.com) to IP addresses (e.g., 192.0.2.1).

• DHCP automates the process of assigning IP addresses to devices on a network, reducing manual configuration.

• Example of DNS: When you enter a website URL, DNS servers find ...read more

Hands-on experience with SQL queries for creating and manipulating tables and table elements.

• Use CREATE TABLE statement to create a new table

• Use ALTER TABLE statement to add, modify, or delete columns in a table

• Use INSERT INTO statement to add new rows of data into a table

• Use UPDATE statement to modify existing data in a table

• Use DELETE statement to remove rows from a table

The data structure implemented in an elevator is a queue.

• Elevator requests are added to the queue in the order they are received.

• The elevator serves requests in a first-come, first-served manner.

• Once a request is completed, it is removed from the queue.

• Example: If someone on the 5th floor requests the elevator, their request is added to the queue and the elevator will serve it after completing any previous request...read more

Infrastructure refers to the basic physical and organizational structures needed for the operation of a society or enterprise.

• Infrastructure includes roads, bridges, buildings, power grids, water supply systems, and communication networks.

• It is essential for the functioning of a society or enterprise.

• Infrastructure can be public or private.

• Examples of public infrastructure include highways, airports, and public tr...read more

The task is to count and eliminate duplicate letters from a string, returning only unique characters.

• Use a set to track unique characters as you iterate through the string.

• For each character, check if it is already in the set.

• If not, add it to the result and the set.

• Example: Input 'hello' -> Output 'helo'.

• Example: Input 'programming' -> Output 'progamin'.

Java is platform independent while C++ is not.

• Java code is compiled into bytecode which can run on any platform with a JVM, while C++ code needs to be compiled separately for each platform.

• Java has automatic memory management through garbage collection, while C++ requires manual memory management.

• Java has built-in support for multithreading, while C++ requires external libraries.

• Java has a simpler syntax and is ea...read more