Software Technologist 1 Interview Questions and Answers

Multi-threaded program to print even and odd numbers up to 100

• Create two threads, one for even numbers and one for odd numbers

• Use a loop to iterate through numbers 1 to 100

• In each iteration, check if the number is even or odd

• Print the number in the corresponding thread

• Join the threads to ensure all numbers are printed in order

I worked on the Observer design pattern

• Observer pattern is used for one-to-many object dependency

• It defines a one-to-many relationship between objects

• When one object changes state, all its dependents are notified and updated automatically

• Example: A weather station that notifies its observers (display devices) when the temperature changes

Virtual DOM security in React refers to the protection of the virtual representation of the DOM from potential security vulnerabilities.

• Virtual DOM in React is a lightweight copy of the actual DOM, which allows React to efficiently update the UI without directly manipulating the real DOM.

• Security in virtual DOM involves preventing cross-site scripting (XSS) attacks by sanitizing user input and using libraries like DOMPurify.

• React's reconciliation process ensures that only the...read more

Find all permutation pairs of given numbers.

• Use recursion to generate all possible permutations of the numbers.

• For each permutation, create a pair of strings with the two numbers swapped.

• Store the pairs in an array of strings.

The n+1 problem in Hibernate refers to the issue of making n+1 database queries instead of a single query when fetching related entities.

• Occurs when fetching a collection of entities and then accessing a lazy-loaded association for each entity individually

• Can be resolved by using fetch joins or batch fetching to reduce the number of queries

• Example: Fetching a list of orders and then accessing the customer for each order separately