Deutsche Telekom Digital Labs Software Engineer Interview Questions and Answers

The project involves creating a web-based platform for online shopping with features like user registration, product browsing, shopping cart, and payment processing.

• User registers on the platform with personal information

• User browses products by category or search

• User adds products to the shopping cart

• User proceeds to checkout and makes payment

• Order is confirmed and user receives a confirmation email

Using Java 8 streams to filter and process a list of employee salaries above a certain threshold.

• Create a list of employee salaries: List<Integer> salaries = Arrays.asList(30000, 50000, 70000, 40000);

• Use streams to filter salaries above 45000: List<Integer> highSalaries = salaries.stream().filter(salary -> salary > 45000).collect(Collectors.toList());

• Calculate the average of the filtered salaries...read more

Checked exceptions are exceptions that must be either caught or declared in the method signature.

• Checked exceptions are subclasses of Exception (excluding RuntimeException and its subclasses)

• Checked exceptions must be either caught using try-catch block or declared in the method signature using 'throws' keyword

• Examples of checked exceptions in Java include IOException, SQLException, and ClassNotFoundException

Program to print even and odd numbers from 1 to 20 using 2 threads alternately.

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

• Use wait(), notify(), and notifyAll() to ensure alternate printing.

• Ensure synchronization between the two threads to avoid race conditions.

• Example: Thread 1 prints even numbers (2, 4, 6, ...) and Thread 2 prints odd numbers (1, 3, 5, ...).

Annotation used to mark a class as a Spring Boot application

• Combines @Configuration, @EnableAutoConfiguration, and @ComponentScan annotations

• Used to bootstrap and launch a Spring application

• Automatically scans for Spring components in the package and sub-packages

ArrayList is better for random access, LinkedList is better for frequent insertions/deletions.

• ArrayList uses dynamic array to store elements, LinkedList uses doubly linked list.

• ArrayList provides fast random access to elements using index, LinkedList provides fast insertion/deletion at any position.

• Example: ArrayList is suitable for scenarios where random access is required like searching, LinkedList is suitable f...read more