Fidelity Investments Lead Developer Interview Questions, Process, and Tips

Q1. Stringbuilder and string buffer diff
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Q2. Where we store the object of string
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Objects of String are stored in the String Pool in Java.
• String objects are stored in the String Pool, a special memory area in Java heap memory.

• String literals are automatically stored in the String Pool.

• String objects created using the new keyword are not stored in the String Pool.

• String.intern() method can be used to store a String object in the String Pool.
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Q3. What is bean in springboot
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A bean in Spring Boot is a Java object that is instantiated, assembled, and managed by the Spring IoC container.
• Beans are defined in the Spring configuration file or using annotations like @Component, @Service, @Repository, etc.

• Beans are singleton by default but can be scoped as prototype, request, session, etc.

• Beans are injected into other beans using dependency injection.

• Example: @Component annotation is used to defi
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Q4. What is query parameters and path param
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Query parameters are used to pass data to a web server through the URL, while path parameters are part of the URL itself.
• Query parameters are key-value pairs added to the end of a URL after a '?'

• Path parameters are variables within the URL path itself, denoted by curly braces {}

• Example of query parameter: www.example.com/api/users?id=123

• Example of path parameter: www.example.com/api/users/{userId}
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Q5. Code snippet related to exception
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Q6. Diff between exception and error
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Exceptions are recoverable errors that can be handled in code, while errors are unrecoverable issues that usually result in program termination.
• Exceptions are checked at compile time, while errors are unchecked.

• Exceptions are subclasses of Throwable, while errors are subclasses of Error.

• Examples of exceptions include FileNotFoundException, NullPointerException, while examples of errors include OutOfMemoryError, StackOv
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Q1. Project questions
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Q2. Spring related questions
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DP graphs strings it was good

Q1. Reverse a linkded list
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Reverse a linked list by changing the direction of pointers
• Start with three pointers: current, previous, and next

• Iterate through the list, updating pointers to reverse the direction

• Return the new head of the reversed list
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Q2. Print fibonacci series
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The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones.
• Start with two variables initialized to 0 and 1

• Loop through desired number of iterations, adding the previous two numbers to get the next number

• Print or store each number in the series
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Q1. Why do you want to switch
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I want to switch to explore new technologies and challenges in a different industry.
• Interested in learning new skills and technologies

• Seeking new challenges and opportunities for growth

• Want to explore different industry perspectives
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Q2. Salry expectations
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Q1. Question on oop concepts
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Q2. Coding questions
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Q1. Ask to write code for equal and hashcode in notepad
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Q2. Type of Collections and its internal working
Ans. 
Java collections are data structures that store and manipulate groups of objects.
• Types of collections include List, Set, Map, Queue, etc.

• Internal workings involve data structures like arrays, linked lists, hash tables, etc.

• Collections framework provides interfaces and classes for working with collections.
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Q3. Count number of occurrence of string from Array
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Count occurrences of a specific string in an array of strings.
• Iterate through the array and use a HashMap to store the count of each string.

• Use the string as key and increment the count each time it is encountered.

• Return the count of the specific string at the end.
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Q4. Write a code using stream
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Using stream to filter a list of strings
• Use the filter method to apply a predicate to each element in the stream

• Convert the stream back to a list using the collect method
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Q1. Spring java and how do you leverage in your project
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I leverage Spring Java for dependency injection, MVC framework, and transaction management in my projects.
• Utilize Spring's dependency injection to manage object dependencies and improve code maintainability

• Leverage Spring MVC framework for building web applications with clean separation of concerns

• Use Spring's transaction management to ensure data integrity and consistency in database operations
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It was just a typical logical reasoning and aptitude MCQ test

There were 2 coding questions and you can select any language for solving it. The test was online

Q1. He simply asked me which coding language I prefer and why ? (Mine was C++)
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Q2. Difference between C and C++?
Ans. 
C is a procedural programming language while C++ is an object-oriented programming language.
• C is a procedural programming language, while C++ supports both procedural and object-oriented programming.

• C does not have classes and objects, while C++ does.

• C does not support function overloading, while C++ does.

• C does not have exception handling, while C++ does.

• C does not have namespaces, while C++ does.
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Q3. What is Object oriented programming?
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Object oriented programming is a programming paradigm based on the concept of objects, which can contain data and code.
• Objects are instances of classes, which define the structure and behavior of the objects.

• Encapsulation, inheritance, and polymorphism are key principles of object oriented programming.

• Example: Inheritance allows a class to inherit properties and methods from another class.

• Example: Encapsulation hides t...read more
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Q4. What are the 4 pillars of OOPs?
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Encapsulation, Inheritance, Polymorphism, Abstraction
• Encapsulation: Bundling data and methods that operate on the data into a single unit

• Inheritance: Ability of a class to inherit properties and behavior from another class

• Polymorphism: Ability to present the same interface for different data types

• Abstraction: Hiding the complex implementation details and showing only the necessary features
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Q5. Write down code implementing all 4 pillars of OOPs.
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Code implementing all 4 pillars of OOPs
• Encapsulation: Encapsulate data within classes and provide public methods to access and modify the data.

• Inheritance: Create a hierarchy of classes where child classes inherit attributes and methods from parent classes.

• Polymorphism: Allow objects of different classes to be treated as objects of a common superclass through method overriding and overloading.

• Abstraction: Hide complex ...read more
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Q6. Difference between Stacks and Queues?
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Stacks are Last In First Out (LIFO) data structures, while Queues are First In First Out (FIFO) data structures.
• Stacks: Elements are added and removed from the same end, like a stack of plates. Example: Undo feature in text editors.

• Queues: Elements are added at the rear and removed from the front, like a line of people waiting. Example: Print queue in a printer.
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Q7. Write a code to find the 2nd largest element in an array.
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Code to find the 2nd largest element in an array
• Sort the array in descending order and return the element at index 1

• Iterate through the array and keep track of the two largest elements

• Handle edge cases like arrays with less than 2 elements
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Q8. What is merge sort and its Algorithm ?
Ans. 
Merge sort is a divide and conquer algorithm that divides the input array into two halves, sorts them recursively, and then merges them.
• Divide the input array into two halves

• Recursively sort each half

• Merge the sorted halves back together
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Q9. What is DBMS and RDBMS and difference between them?
Ans. 
DBMS stands for Database Management System, while RDBMS stands for Relational Database Management System. RDBMS is a type of DBMS.
• DBMS is a software system that allows users to define, create, maintain and control access to the database.

• RDBMS is a type of DBMS that stores data in a structured format using tables with rows and columns.

• RDBMS enforces a set of rules called ACID properties to ensure data integrity, while D...read more
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Q10. What is SQL and who its different from mySQL?
Ans. 
SQL is a standard language for managing databases, while MySQL is a specific open-source relational database management system.
• SQL stands for Structured Query Language and is used to communicate with databases.

• SQL is a standard language that can be used with various database management systems.

• MySQL is a specific open-source relational database management system that uses SQL.

• MySQL is one of the most popular database m...read more
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Q11. Difference between Delete, Truncate and Drop?
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Delete removes specific rows from a table, Truncate removes all rows from a table, and Drop removes the table itself.
• Delete is a DML command that removes specific rows from a table based on a condition.

• Truncate is a DDL command that removes all rows from a table but keeps the table structure.

• Drop is a DDL command that removes the entire table along with its structure.
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Q12. Different kind of Joins in DBMS ?
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Different types of joins in DBMS include inner join, outer join, left join, right join, and full join.
• Inner join: Returns rows when there is a match in both tables.

• Outer join: Returns all rows from one table and only matching rows from the other table.

• Left join: Returns all rows from the left table and the matched rows from the right table.

• Right join: Returns all rows from the right table and the matched rows from the ...read more
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Q13. And at last 2 to 3 SQL queries. They were not that hard, Just basic queries.
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