600+ Application Developer Interview Questions and Answers

To efficiently manage room bookings and prebookings in a hotel, a priority queue data structure can be implemented.

• A priority queue can be used to prioritize room bookings based on check-in dates.

• When a customer checks out, the room becomes available and can be assigned to the next customer in the priority queue.

• Prebookings can be stored separately and checked against the availability of rooms before assigning them to customers.

• The priority queue can be implemented using a bi...read more

Finding the greatest common divisor (GCD) of two given numbers 'X' and 'Y'.

• Iterate through each test case

• Use Euclidean algorithm to find GCD

• Output the GCD for each test case

Ansible playbooks automate configuration management. CI/CD pipeline automates software delivery. Tools include Jenkins, GitLab, and Travis CI.

• Ansible playbooks are written in YAML format and define tasks to be executed on remote hosts.

• CI/CD pipeline automates the software delivery process from code commit to production deployment.

• Tools for pipeline creation include Jenkins, GitLab, Travis CI, and CircleCI.

• Pipeline creation involves defining stages, jobs, and triggers to autom...read more

Yes, I can write a SQL query to join two tables on a common attribute and select matching records.

• Use INNER JOIN to join tables A and B on the common attribute ID

• Select the records (ID_NAME) where ID values match in both tables

Java is platform independent because the code is compiled into bytecode that can run on any system with a JVM, which is platform dependent.

• Java code is compiled into bytecode, which is a platform-independent intermediate code

• The JVM interprets and executes the bytecode on different platforms, making it platform dependent

• The JVM acts as a layer of abstraction between the Java code and the underlying operating system

• Example: A Java program compiled on a Windows machine can run ...read more

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.

Minimum 7 races required to find the top 3 fastest horses.

• Divide the 25 horses into 5 groups of 5 horses each.

• Conduct a race among the horses in each group to determine the fastest horse in each group.

• Take the top 2 horses from each group and conduct a race among them to determine the fastest horse overall.

• The winner of this race is the fastest horse.

• Now, take the second-place horse from the final race and the second-place horse from each group race.

• Conduct a race among these...read more

The @RestController annotation is a specialized version of the @Controller annotation in Spring MVC.

• The @Controller annotation is used to define a controller class in Spring MVC.

• The @RestController annotation is used to define a RESTful web service controller.

• The @RestController annotation is a combination of @Controller and @ResponseBody annotations.

• The @Controller annotation returns a view while the @RestController annotation returns data in JSON or XML format.

• Example: @Con...read more

Create an array of song titles sorted by year of publication.

• Create an array of song objects with properties for title and year of publication.

• Sort the array by year of publication.

• Extract the titles of the songs into a separate array.

• Return the array of song titles.

Print all possible paths from start to end in a linear way, moving either one or two steps right.

• Use dynamic programming to solve the problem

• Create a 2D array to store the number of paths to each position

• Start from the end position and work backwards

• At each position, calculate the number of paths by summing the number of paths from the next two positions

• Print all the paths by backtracking from the start position

Create a function to count character occurrences in a string and format the result as 'letter followed by count'.

• Use a dictionary to count occurrences of each character.

• Iterate through the string and update counts in the dictionary.

• Construct the output string by concatenating each character with its count.

• Example: For 'aabb', the output should be 'a2b2'.

• Example: For 'abc', the output should be 'a1b1c1'.

A snail climbs a 30ft ramp at 3ft/hour up and 2ft/hour down. Calculate the time to reach the top.

• The snail effectively climbs 1ft for every hour (3ft up - 2ft down).

• To climb 30ft, it will take 30 hours (30ft / 1ft per hour).

• The snail's net progress is crucial to determine the total time.

It depends on the use case. QuickSort is generally the fastest, but MergeSort is more stable and efficient for larger datasets.

• QuickSort is generally the fastest sorting algorithm, but can be unstable for certain datasets.

• MergeSort is more stable and efficient for larger datasets, but can be slower than QuickSort for smaller datasets.

• InsertionSort is efficient for small datasets, but can be slow for larger datasets.

• HeapSort is efficient for larger datasets, but can be slower ...read more

Method overloading is when multiple methods in the same class have the same name but different parameters. Method overriding is when a subclass provides a specific implementation of a method that is already provided by its superclass.

• Method overloading allows a class to have multiple methods with the same name but different parameters. For example, having multiple constructors in a class with different parameter lists.

• Method overriding occurs when a subclass provides a specif...read more

The words in a string can be arranged based on their order of occurrence.

• Split the string into an array of words

• Create a dictionary to store the count of each word

• Sort the array based on the count of each word

• Join the sorted array back into a string

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.

Interview questions for application developer including Python applications, PEP8, CSS, input handling, list vs tuples, and willingness to relocate.

• Python is used for web development, data analysis, machine learning, and more

• PEP8 is a style guide for Python code

• CSS stands for Cascading Style Sheets and is used for styling web pages

• To find input3, use input3 = input1 + input2

• To resolve issues with colleagues, communicate and collaborate effectively

• Lists and tuples are both use...read more

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<>();

Probability of a stone thrown in a circle with radius r lying near the center.

• The probability of the stone lying near the center is directly proportional to the area of the circle near the center.

• The area of the circle near the center is proportional to the square of the radius.

• Therefore, the probability of the stone lying near the center is proportional to the square of the radius.

• The probability can be calculated by dividing the area of the circle near the center by the tot...read more

Abstract classes in Java are classes that cannot be instantiated and are used as blueprints for other classes.

• Abstract classes cannot be instantiated, meaning you cannot create objects of an abstract class.

• Abstract classes can have both abstract and non-abstract methods.

• Interfaces in Java are similar to abstract classes, but they cannot have any method implementations.

• A class can implement multiple interfaces, but it can only extend one abstract class.

• Abstract classes can hav...read more

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.

Clustered index physically reorders the data in the table, while non-clustered index does not.

• Clustered index determines the physical order of data in the table, while non-clustered index does not.

• A table can have only one clustered index, but multiple non-clustered indexes.

• Clustered index is faster for retrieval of data, as it directly points to the actual data rows.

• Non-clustered index is faster for retrieval of specific data, as it points to a separate list of pointers to t...read more

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 code inserts two numbers in a text file, ensuring that the second number is greater than the first and there is no overlap between entries.

• Read the existing entries from the text file

• Check if the new numbers satisfy the conditions

• If conditions are met, insert the new numbers into the file

• Otherwise, display an error message

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