CGI Group Software Engineer Interview Questions, Process, and Tips for Experienced

A callback is a function that is passed as an argument to another function and is executed after a certain event occurs.

• Callback functions are commonly used in event handling, asynchronous programming, and APIs.

• They allow for more flexible and modular code by separating concerns.

• Example: setTimeout function in JavaScript takes a callback function as an argument to be executed after a specified time.

Yes, a callback function is a function that is passed as an argument to another function.

• Callback functions are commonly used in event handling, asynchronous programming, and functional programming.

• Example: setTimeout(function() { console.log('Hello!'); }, 1000);

• Example: array.map(function(item) { return item * 2; });

Marker interfaces are interfaces with no methods, used to mark classes for special treatment.

• Marker interfaces have no methods, they simply mark a class as having a certain property or behavior.

• Examples include Serializable interface in Java, which marks a class as serializable for object serialization.

• Another example is Cloneable interface in Java, which marks a class as cloneable for object cloning.

Two common design patterns used in projects are Singleton and Observer patterns.

• Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Observer pattern defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

Time complexity of hashmap operations is O(1) on average, but can be O(n) in worst case.

• HashMap operations like get, put, remove have constant time complexity O(1) on average due to hashing

• In worst case scenario, all keys hash to the same bucket resulting in linear search O(n)

• Rehashing occurs when load factor exceeds a threshold, increasing time complexity temporarily

Spring beans can have different scopes like singleton, prototype, request, session, and application.

• Singleton scope: Bean is created only once per Spring IoC container

• Prototype scope: Bean is created each time it is requested

• Request scope: Bean is created once per HTTP request

• Session scope: Bean is created once per HTTP session

• Application scope: Bean is created once per ServletContext

To improve performance of a Spring Boot application, consider optimizing database queries, caching, using asynchronous processing, and monitoring performance metrics.

• Optimize database queries by using indexes, avoiding N+1 queries, and limiting the amount of data fetched.

• Implement caching to store frequently accessed data in memory, reducing the need to fetch data from the database repeatedly.

• Use asynchronous processin...read more

Implemented logging in Spring Boot application using SLF4J and Logback

• Added dependencies for SLF4J and Logback in pom.xml

• Configured logback.xml for logging levels and appenders

• Injected Logger instances using @Autowired annotation in classes

• Used logger.debug(), logger.info(), logger.error() methods for logging