20+ Fujitsu Application Developer Interview Questions and Answers

Reverse a singly linked list of integers and return the head of the reversed linked list.

• Iterate through the linked list and reverse the pointers to point to the previous node instead of the next node.

• Use three pointers to keep track of the current, previous, and next nodes while reversing the linked list.

• Update the head of the reversed linked list as the last node encountered during the reversal process.

JVM allocates 5 types of memory areas: Heap, Stack, Method Area, PC Register, and Native Method Stack.

• Heap is used for storing objects and is shared among all threads.

• Stack is used for storing method calls and local variables, each thread has its own stack.

• Method Area stores class structures, method data, and static variables.

• PC Register stores the address of the currently executing instruction.

• Native Method Stack is used for native method calls.

Spring Boot offers basic annotations like @SpringBootApplication, @RestController, @Autowired, @RequestMapping, @ComponentScan.

• @SpringBootApplication - Used to mark the main class of a Spring Boot application.

• @RestController - Used to define RESTful web services.

• @Autowired - Used for automatic dependency injection.

• @RequestMapping - Used to map web requests to specific handler methods.

• @ComponentScan - Used to specify the base packages to scan for Spring components.

ArrayList is non-synchronized and Vector is synchronized in Java.

• ArrayList is not synchronized, while Vector is synchronized.

• ArrayList is faster than Vector as it is not synchronized.

• Vector is thread-safe, while ArrayList is not.

• Example: ArrayList<String> list = new ArrayList<>(); Vector<String> vector = new Vector<>();

The starter dependency of the Spring Boot module is spring-boot-starter-parent.

• The starter dependency provides a set of default configurations and dependencies for Spring Boot applications.

• It helps in reducing the amount of boilerplate code needed to set up a Spring Boot project.

• The spring-boot-starter-parent is typically used as the parent project in a Spring Boot application's pom.xml file.

Different types of waits in Selenium WebDriver include Implicit Wait, Explicit Wait, and Fluent Wait.

• Implicit Wait: Waits for a certain amount of time before throwing a NoSuchElementException.

• Explicit Wait: Waits for a certain condition to occur before proceeding further in the code.

• Fluent Wait: Waits for a condition to be true with a specified polling frequency and timeout.

HashSet is a collection of unique elements, while HashMap is a key-value pair collection.

• HashSet does not allow duplicate elements, while HashMap allows duplicate values but not duplicate keys.

• HashSet uses a hash table to store elements, while HashMap uses key-value pairs to store data.

• Example: HashSet<String> set = new HashSet<>(); HashMap<String, Integer> map = new HashMap<>();

The @RestController annotation in Spring Boot is used to define a class as a RESTful controller.

• It is a specialized version of the @Controller annotation that is used to create RESTful web services.

• It eliminates the need for annotating each method with @ResponseBody as it combines @Controller and @ResponseBody annotations.

• It is typically used to build RESTful web services that return JSON or XML data.

• Example: @RestController public class UserController { @GetMapping("/users")...read more

The @SpringBootApplication annotation is used to mark the main class of a Spring Boot application.

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

• Enables the application to start with a main method

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

ConcurrentHashMap is a thread-safe implementation of the Map interface in Java.

• ConcurrentHashMap allows multiple threads to read and write to the map concurrently without causing any inconsistencies.

• It achieves thread-safety by dividing the map into segments, each of which can be locked independently.

• ConcurrentHashMap uses a technique called lock striping to minimize contention and improve performance.

• It does not throw ConcurrentModificationException during iteration as it wo...read more

Regular expression for 10-digit numeric characters starting with 1, 2, or 3.

• Use the pattern ^[1-3]\d{9}$ to match the criteria

• The ^ symbol denotes the start of the string

• The [1-3] specifies that the first digit must be 1, 2, or 3

• \d{9} matches exactly 9 numeric digits

• $ indicates the end of the string

Data encapsulation is the concept of bundling data with the methods that operate on that data within a class.

• Data encapsulation restricts access to certain components of an object, protecting the data from external interference.

• It allows for better control over the data by hiding the implementation details and only exposing necessary information through methods.

• Encapsulation helps in achieving data abstraction, where the internal representation of an object is hidden from the...read more

A join in SQL is used to combine rows from two or more tables based on a related column between them.

• Types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• INNER JOIN returns rows when there is at least one match in both tables.

• 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 left table.

• FULL JOIN returns rows when there is a match in one of t...read more

No, static methods cannot be overridden in Java.

• Static methods belong to the class itself, not to any specific instance of the class.

• Subclasses can define static methods with the same signature as the parent class, but it is not considered overriding.

• Example: Parent class has a static method 'display()', and subclass also has a static method 'display()'. These are two separate methods, not overriding each other.

findElement() returns the first matching element on the web page, while findElements() returns a list of all matching elements.

• findElement() returns a single WebElement matching the locator provided.

• findElements() returns a list of WebElements matching the locator provided.

• If no elements are found, findElement() will throw a NoSuchElementException, while findElements() will return an empty list.

OOPS stands for Object-Oriented Programming System. It is a programming paradigm based on the concept of objects.

• OOPS focuses on creating objects that contain data in the form of fields (attributes) and code in the form of procedures (methods).

• Encapsulation, inheritance, and polymorphism are key principles of OOPS.

• Encapsulation refers to the bundling of data and methods that operate on the data into a single unit (object).

• Inheritance allows a class to inherit properties and b...read more

Dependency injection is a design pattern where components are given their dependencies rather than creating them internally.

• Allows for easier testing by providing mock dependencies

• Promotes loose coupling between components

• Improves code reusability and maintainability

• Examples: Constructor injection, Setter injection, Interface injection

Basic SQL skills include querying databases, manipulating data, and understanding database structures.

• Writing basic SQL queries to retrieve data from databases

• Understanding and using SQL functions and operators

• Creating and modifying database tables and relationships

• Using SQL to filter, sort, and group data

• Understanding basic SQL syntax and commands

SQL is a language used to manage and query databases, PL/SQL is an extension that adds procedural programming capabilities.

• SQL is used for querying and manipulating data in databases.

• PL/SQL is a procedural language extension for SQL, allowing for more complex logic and programming capabilities.

• Data structures in SQL refer to the way data is organized and stored in tables.

• PL/SQL allows for the creation of custom data structures using variables, arrays, and records.

• Differences ...read more

To convert hours into seconds, multiply the number of hours by 3600.

• Multiply the number of hours by 3600 to get the equivalent seconds.

• For example, 2 hours = 2 * 3600 = 7200 seconds.

I have used a variety of programming languages including Java, Python, C++, and JavaScript.

• Java

• Python

• C++

• JavaScript

SQL is a language used for managing and querying databases, while PL/SQL is an extension of SQL used for procedural programming.

• SQL stands for Structured Query Language and is used for managing and querying relational databases.

• PL/SQL stands for Procedural Language/SQL and is an extension of SQL that adds procedural programming capabilities.

• SQL is used to retrieve and manipulate data in databases using queries like SELECT, INSERT, UPDATE, DELETE.

• PL/SQL allows for the creation...read more

Forms are used to input data while reports are used to display data.

• Forms are used to collect and input data into a system.

• Reports are used to display and present data in a structured format.

• Forms are interactive and allow users to input data, while reports are static and provide information based on the data entered.

• Examples: A registration form on a website vs. a sales report generated from a database.

Spring MVC is a framework for building web applications in Java, following the Model-View-Controller design pattern.

• Spring MVC follows the Model-View-Controller design pattern, where the model represents the data, the view represents the UI, and the controller handles the user input.

• It provides components like DispatcherServlet, Controller, Model, and ViewResolver to handle requests and responses.

• It supports the use of annotations like @Controller, @RequestMapping, and @Model...read more