20+ Interview Questions and Answers

Using Java 8, find the first non-repeating character in a string.

• Use Java 8 streams to convert the string to a character array.

• Use Collectors.groupingBy to group characters by count.

• Filter out characters with count > 1 and find the first character with count 1.

Sum of all even numbers without using inbuild methods using stream api

• Create an array of numbers

• Use stream to filter out even numbers

• Use stream to sum up the filtered even numbers

Intermediate and terminal operators are used in Java streams to perform intermediate and terminal operations on elements.

• Intermediate operators are used to transform, filter, or manipulate elements in a stream before passing them to the next operation. Examples include map(), filter(), and sorted().

• Terminal operators are used to trigger the processing of elements in a stream and produce a result. Examples include forEach(), collect(), and reduce().

To find the root cause, use problem-solving techniques like the 5 Whys, fishbone diagram, and Pareto analysis.

• Use the 5 Whys technique to repeatedly ask 'why' until the underlying cause is identified.

• Create a fishbone diagram to visually analyze potential causes across different categories.

• Apply Pareto analysis to prioritize potential causes based on their frequency or impact.

• Collect and analyze data to identify patterns or trends that may indicate the root cause.

• Consider usi...read more

Exception handling in Spring Boot allows developers to gracefully handle errors and provide meaningful responses to users.

• Use @ControllerAdvice to handle exceptions globally

• Use @ExceptionHandler to handle specific exceptions

• Return custom error messages or responses to users

Program to check prime number and reverse a string

• For checking prime number, iterate from 2 to n/2 and check if n is divisible by any number

• For reversing a string, use a loop to iterate through the characters and build the reversed string

Various methods in RestApi include GET, POST, PUT, DELETE.

• GET - Used to retrieve data from the server. Example: GET /users

• POST - Used to send data to the server to create a new resource. Example: POST /users

• PUT - Used to update an existing resource on the server. Example: PUT /users/1

• DELETE - Used to delete a resource on the server. Example: DELETE /users/1

Sort an ArrayList of objects by age.

• Create a custom Comparator to compare the age of the objects.

• Use the Collections.sort() method to sort the ArrayList using the custom Comparator.

• Ensure that the objects in the ArrayList have a field for age.

IOC is a design pattern where control is inverted, while DI is a technique to achieve IOC by injecting dependencies into a class.

• IOC stands for Inversion of Control, where the control of flow is inverted from the traditional top-down approach.

• DI stands for Dependency Injection, a technique used to implement IOC by injecting dependencies into a class from an external source.

• IOC is a design principle, while DI is a technique to achieve IOC.

• Example: In IOC, a framework controls ...read more

Annotation used in Spring framework to bind the HTTP request body to a method parameter.

• Used in Spring MVC to indicate that a method parameter should be bound to the body of the web request.

• Can be used with various data types like JSON, XML, etc.

• Helps in simplifying the process of handling request data in Spring applications.

Type casting in Java is the process of converting one data type into another.

• Type casting can be done implicitly or explicitly in Java.

• Implicit type casting is done when a smaller data type is converted to a larger data type, while explicit type casting is done when a larger data type is converted to a smaller data type.

• Example of implicit type casting: int num = 10; double result = num;

• Example of explicit type casting: double num = 10.5; int result = (int) num;

Functional interface in Java is an interface with only one abstract method. It can have multiple default or static methods.

• Functional interfaces can be annotated with @FunctionalInterface to ensure they have only one abstract method.

• Examples of functional interfaces in Java include Runnable, Callable, and ActionListener.

• Lambda expressions can be used to implement functional interfaces concisely.

I communicate technically by providing clear and concise instructions, troubleshooting issues, and offering solutions to customers.

• Provide step-by-step instructions for technical issues

• Use simple language to explain complex technical concepts

• Offer alternative solutions if the initial suggestion does not work

• Listen actively to understand the customer's problem before providing a solution

Singleton class ensures only one instance of a class is created and provides a global point of access to it.

• Use a private static variable to hold the instance of the class.

• Make the constructor private to prevent instantiation from outside the class.

• Provide a static method to access the instance, creating it if necessary.

To reduce rejection, implement quality control measures, improve processes, train employees, and analyze root causes.

• Implement quality control measures such as inspections, testing, and audits

• Improve processes by identifying bottlenecks, streamlining workflows, and implementing automation

• Train employees on quality standards, procedures, and problem-solving techniques

• Analyze root causes of rejection to identify recurring issues and implement corrective actions

• Establish clear c...read more

Asynchronous programming allows tasks to run concurrently, but can lead to complex code and potential race conditions.

• Difficult to debug due to non-linear flow of execution

• Potential for race conditions when multiple tasks access shared resources

• Complex error handling and callback hell can make code hard to read and maintain

Consignment stock is inventory that is owned by a supplier but held by a customer until it is sold.

• Consignment stock is a type of inventory management where the supplier retains ownership of the goods until they are sold by the customer.

• The supplier only invoices the customer for the goods that have been sold, not for the entire consignment stock.

• Consignment stock is often used in industries where the goods have a long shelf life, such as automotive or electronics.

• Types of co...read more

Deploying a product involves planning, coordinating, and executing various tasks to ensure successful product launch.

• Develop a deployment plan outlining tasks, timelines, and responsibilities.

• Coordinate with cross-functional teams such as production, engineering, and quality assurance.

• Ensure availability of necessary resources and materials for production.

• Conduct pre-production testing and quality checks.

• Manage production schedules and monitor progress.

• Implement efficient pro...read more

ref and out are keywords in C# used for passing arguments to methods by reference.

• ref keyword is used to pass arguments by reference, allowing the method to modify the value of the argument

• out keyword is similar to ref, but the argument does not have to be initialized before being passed to the method

• Example: void UpdateValue(ref int num) { num = num * 2; }

• Example: void GetValues(out int a, out int b) { a = 10; b = 20; }

BFS explores neighbors before moving to next level, while DFS explores as far as possible before backtracking.

• BFS uses a queue to keep track of nodes to visit next, while DFS uses a stack or recursion.

• BFS is optimal for finding shortest path in unweighted graphs, while DFS is more memory efficient.

• BFS is typically implemented iteratively, while DFS can be implemented recursively.

• Example: BFS is used in level order traversal of a binary tree, while DFS is used in pathfinding a...read more

Comparator is used to compare objects of a class, while Comparable is implemented by a class to define its natural ordering.

• Comparator is used when we want to compare objects of different classes or when we want to define multiple sorting criteria.

• Comparable is used when we want to define the default natural ordering of a class.

• Comparator interface is implemented separately from the class being compared.

• Comparable interface is implemented by the class itself.

• Comparator uses t...read more

Events are a higher-level concept that allows objects to communicate without knowing each other, while delegates are a type-safe function pointers.

• Events are based on the observer design pattern, where an object (the publisher) maintains a list of other objects (subscribers) that are interested in being notified when a certain event occurs.

• Delegates are similar to function pointers in C++, but with type safety and object-oriented features. They allow a method to be passed aro...read more

Tf state files are files generated by Terraform to store the state of your infrastructure.

• Tf state files store information about the resources managed by Terraform

• They help Terraform track the current state of your infrastructure

• Tf state files should be stored securely to prevent unauthorized access

A business rule is a server-side script that runs when a record is displayed, inserted, updated, deleted, or when a table is queried.

• Business rules are used to enforce data consistency and automate processes.

• They can be used to set field values, run scripts, or display messages.

• Business rules can be triggered by various actions such as onBefore, onAfter, onDisplay, etc.

HashMap is not inherently international, but can be used in international contexts.

• HashMap is a data structure in Java that stores key-value pairs.

• It does not have any built-in international functionality.

• However, it can be used in international contexts by storing internationalized keys or values.

• For example, you can store translations of keys or values in different languages.

Load balancers distribute incoming network traffic across multiple servers to ensure no single server is overwhelmed.

• Hardware load balancers

• Software load balancers

• Cloud-based load balancers

• DNS-based load balancers