IBM Senior Software Engineer Interview Questions and Answers

Java 8 introduced several new features including lambda expressions, streams, and functional interfaces.

• Lambda expressions: Allow for more concise and readable code by enabling functional programming.

• Streams: Provide a way to work with collections of objects in a more functional style.

• Functional interfaces: Interfaces with a single abstract method, used to enable lambda expressions.

• Optional class: Helps to avoid null p...read more

Spring boot annotations are used to simplify the development process by providing metadata to the Spring framework.

• 1. @SpringBootApplication - Main annotation to indicate the main class of a Spring Boot application.

• 2. @RestController - Annotation for RESTful web services.

• 3. @Autowired - Dependency injection annotation.

• 4. @GetMapping, @PostMapping, @PutMapping, @DeleteMapping - Annotations for mapping HTTP requests to c...read more

String Builder is not synchronized and faster, while String Buffer is synchronized and slower.

• String Builder is not thread-safe, while String Buffer is thread-safe.

• String Builder is faster due to lack of synchronization, while String Buffer is slower due to synchronization.

• String Builder is recommended for single-threaded operations, while String Buffer is recommended for multi-threaded operations.

String pool is a storage area in memory where strings are stored to optimize memory usage by reusing common strings.

• String pool helps in reducing memory usage by storing only one copy of each unique string.

• Strings created using double quotes are stored in the string pool.

• Strings created using new keyword are not stored in the string pool.

There are two main types of memory in a computer system: stack memory and heap memory.

• Stack memory is used for static memory allocation and is managed by the compiler. It is typically faster but limited in size.

• Heap memory is used for dynamic memory allocation and is managed by the programmer. It is slower but has a larger size.

• Examples: C programming language uses stack memory for function calls and heap memory for dy...read more

Longest common subsequence is the longest sequence of characters that appear in the same order in both strings.

• Use dynamic programming to solve this problem efficiently.

• Create a 2D array to store the lengths of longest common subsequences of substrings.

• Traverse the array to find the longest common subsequence.

Find the maximum values in each sliding window of a given array efficiently.

• Use a deque to store indices of array elements in the current window.

• Maintain the deque in decreasing order of values to ensure the front is the max.

• Slide the window by removing elements that are out of bounds and adding new elements.

• Example: For array [1, 3, -1, -3, 5, 3, 6, 7] and window size 3, max values are [3, 3, 5, 5, 6, 7].

Find the equilibrium index in an array where the sum of elements before equals the sum after the index.

• Definition: An equilibrium index is an index in an array where the sum of elements on the left equals the sum on the right.

• Example: In the array [1, 3, 5, 2, 2], the equilibrium index is 2 because 1+3 = 2+2.

• Approach: Calculate the total sum of the array, then iterate through the array while maintaining a running sum o...read more

To protect a site from spam, implement CAPTCHA, use spam filters, validate user input, and monitor site activity. To create a multi-site, use a content management system with multi-site capabilities.

• Implement CAPTCHA to prevent automated spam submissions

• Use spam filters to detect and block spam content

• Validate user input to ensure data integrity and prevent malicious code injection

• Monitor site activity for suspicious b...read more

Roles and responsibilities of a Senior Software Engineer involve leading technical projects, mentoring junior developers, collaborating with cross-functional teams, and ensuring code quality and scalability.

• Leading technical projects and providing technical guidance to team members

• Mentoring junior developers and helping them grow in their technical skills

• Collaborating with cross-functional teams such as product manager...read more