Fidelity Investments Senior Java Developer Interview Questions and Answers

Code for rand7 using rand5 function

• Use rand5 twice to generate a number in [1,25] with equal probability

• If the number is greater than 21, discard and try again

• Otherwise, return (number mod 7) + 1

LRU cache is implemented using a doubly linked list and a hash map.

• Create a doubly linked list to keep track of the order of elements in the cache.

• Create a hash map to store the key-value pairs of the cache.

• When a new element is added, check if the cache is full. If it is, remove the least recently used element from the linked list and the hash map.

• When an element is accessed, move it to the front of the linked list to...read more

Function to randomly select pivot element in Quick Sort

• Generate a random index within the range of the array

• Return the element at the randomly generated index as the pivot

Yes, the string class can be extended in most programming languages.

• Inheritance can be used to extend the functionality of the string class.

• By creating a new class that inherits from the string class, additional methods and properties can be added.

• Extending the string class allows for customization and adding specific functionality to strings.

• Example: In Python, the string class can be extended by creating a new class

Implicit objects in JSP are predefined objects that are available for use without any declaration or initialization.

• Implicit objects in JSP include request, response, session, application, out, config, pageContext, page, exception, and others.

• These objects provide access to various aspects of the JSP environment and can be used to perform common tasks.

• For example, the request object allows access to HTTP request parame...read more

A hash map is a data structure that uses a hash function to map keys to values.

• Hash map stores key-value pairs

• It uses a hash function to compute an index for each key

• Collisions can occur when two keys hash to the same index

• Hash maps provide fast access to values based on their keys

StringBuffer and StringBuilder are both used to manipulate strings, but StringBuffer is thread-safe while StringBuilder is not.

• StringBuffer is synchronized, making it safe for use in multi-threaded environments.

• StringBuilder is not synchronized, making it faster but not thread-safe.

• StringBuffer is preferred when multiple threads are involved, while StringBuilder is preferred for single-threaded scenarios.

• Both classes p...read more

MVC is a software architectural pattern that separates an application into three main components: Model, View, and Controller.

• Model represents the data and business logic of the application.

• View is responsible for displaying the user interface.

• Controller handles user input, updates the model, and interacts with the view.

• MVC promotes separation of concerns and modularity in software development.

• Example: In a web applica...read more

Annotations used in RESTful web services

• 1. @Path - Specifies the URI path for the resource

• 2. @GET - Specifies that the method handles HTTP GET requests

• 3. @POST - Specifies that the method handles HTTP POST requests

• 4. @PUT - Specifies that the method handles HTTP PUT requests

• 5. @DELETE - Specifies that the method handles HTTP DELETE requests

• 6. @PathParam - Binds the value of a URI template parameter to a method paramete...read more

Multi tasking, multi processing, and multi programming are different approaches to managing tasks in an operating system.

• Multi tasking allows multiple tasks to run concurrently on a single processor.

• Multi processing involves multiple processors running tasks simultaneously.

• Multi programming allows multiple programs to be loaded into memory and executed concurrently.

• Examples of multi tasking operating systems include Wi...read more

Memory allocation refers to the process of assigning memory to programs during runtime.

• Stack allocation is done automatically and is limited in size.

• Heap allocation is done manually and is larger in size.

• Stack memory is used for local variables and function calls.

• Heap memory is used for dynamic memory allocation.

• Memory leaks can occur if heap memory is not properly managed.

Use a shared variable and synchronization mechanisms to ensure natural order printing of numbers.

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

• Use a shared variable to keep track of the current number to be printed.

• Implement synchronization mechanisms like locks or semaphores to ensure only one thread can access the shared variable at a time.

• Each thread should check if it is i...read more

Printing a matrix in spiral order

• Start from the first element and print it

• Move in a spiral order towards the center of the matrix

• Repeat until all elements are printed

Thread class and Runnable Interface are used for multithreading in Java.

• Thread class is a predefined class in Java that provides methods to create and control threads.

• Runnable interface is used to define a task that can be executed by a thread.

• Thread class implements Runnable interface.

• Thread class provides more control over threads than Runnable interface.

• Example: Thread t = new Thread(new MyRunnable()); t.start();

• Exa...read more

Linked List is a dynamic data structure while ArrayList is a static data structure.

• Linked List is best for frequent insertion and deletion operations.

• ArrayList is best for frequent access operations.

• Linked List uses more memory than ArrayList.

• ArrayList is faster than Linked List for accessing elements.

• Use Linked List when you need to frequently add or remove elements from the list.

• Use ArrayList when you need to frequen

I am not interested in a career in investment banking.

• I am more interested in a career in software development

• I enjoy problem-solving and creating innovative solutions through coding

• Investment banking does not align with my passion and skill set

I have chosen to apply to J.P. Morgan because of their reputation, global presence, and opportunities for growth.

• J.P. Morgan has a strong reputation in the financial industry.

• They have a global presence with offices in multiple countries.

• The company offers various opportunities for career growth and development.

• J.P. Morgan is known for its innovative technology solutions in the financial sector.

• I am impressed by their ...read more

Yes, I have made a mistake in my previous project.

• I underestimated the complexity of a task and ended up missing the deadline.

• I failed to properly test a feature, resulting in a bug that affected user experience.

• I accidentally deleted an important file without having a backup.

• I misunderstood a requirement and implemented a feature incorrectly.