10+ Fiserv Interview Questions and Answers

Coding questions on string manipulation and sorting algorithms.

• For removing a substring and sorting alphabetically, use string manipulation and sorting functions.

• To reverse a string, use a loop to iterate through the string and append each character to a new string in reverse order.

• For bubble sort, use nested loops to compare adjacent elements and swap them if they are in the wrong order.

Partial is used to render a specific portion of a view, while render partial is used to render a partial view within another view in MVC.

• Partial is used to render a specific portion of a view in MVC.

• Render partial is used to render a partial view within another view in MVC.

• Partial can be used to render a reusable piece of code in multiple views.

• Render partial is useful for rendering common elements like headers or footers in multiple views.

• Example: <%= render partial: 'header...read more

Use LWC wire method to trigger event communication from child to parent and calculate sum

• Create a custom event in the child component to pass data to the parent component

• Use @wire method in the parent component to listen for the custom event and calculate the sum

• Integrate with a REST API to fetch additional data if needed

Performance metrics in Machine Learning measure the effectiveness and efficiency of models.

• Accuracy: measures the proportion of correct predictions out of the total predictions made by the model.

• Precision: measures the proportion of true positive predictions out of all positive predictions made by the model.

• Recall: measures the proportion of true positive predictions out of all actual positive instances in the dataset.

• F1 Score: a combination of precision and recall, providing...read more

To access the API deployed behind the VPC, you can set up a VPN connection or use a bastion host.

• Set up a VPN connection to the VPC to securely access the API

• Use a bastion host as a jump server to access the API

• Ensure proper security group and network ACL configurations to allow access to the API from specific IP addresses

After training a model, I can improve it by fine-tuning hyperparameters, increasing the size of the training dataset, or implementing ensemble methods.

• Fine-tune hyperparameters such as learning rate, batch size, and regularization strength to optimize model performance.

• Increase the size of the training dataset by collecting more data or using data augmentation techniques to improve generalization.

• Implement ensemble methods like bagging or boosting to combine multiple models f...read more

Flexible means adaptable to change or able to be modified easily.

• Being able to adjust to new requirements or situations

• Having the ability to change or modify code without breaking it

• Being open to feedback and willing to make changes

• Allowing for customization or configuration options

• Examples: using variables instead of hardcoding values, implementing a plugin system

Validation in MVC ensures data entered by user meets specified criteria before processing.

• Validation can be done using data annotations in model classes.

• Validation can also be performed using ModelState.IsValid in controller actions.

• Client-side validation can be implemented using JavaScript libraries like jQuery Validate.

String is immutable to ensure thread safety and prevent unintended modification.

• Immutable strings can be safely shared across multiple threads without the risk of race conditions.

• Immutable strings prevent unintended modification, which can cause unexpected behavior in the program.

• String interning is possible because of immutability, which allows for efficient memory usage.

• Examples of immutable classes in Java include String, Integer, and Boolean.

MDC logging is used to enrich log messages with contextual information specific to each thread or user.

• MDC stands for Mapped Diagnostic Context

• It allows developers to include additional information in log messages without modifying the log message itself

• Useful for tracking user sessions, request IDs, or any other contextual information

• Commonly used in multi-threaded applications to differentiate log messages from different threads

Create a Lightning Web Component (LWC) using a combobox

• Use the lightning-combobox component in your LWC template

• Define options for the combobox in your JavaScript file

• Handle selection changes using event handlers

Encapsulation is the process of hiding internal details of an object and providing access only through defined methods.

• Encapsulation is a fundamental principle of object-oriented programming.

• It helps in achieving data abstraction and data hiding.

• By encapsulating data and methods together, it ensures data integrity and security.

• Encapsulation allows for easy modification of internal implementation without affecting the external code that uses the object.

• Access to the encapsulat...read more

ACID properties ensure database transactions are reliable and consistent.

• ACID stands for Atomicity, Consistency, Isolation, and Durability.

• Atomicity ensures that a transaction is treated as a single, indivisible unit of work.

• Consistency ensures that a transaction brings the database from one valid state to another.

• Isolation ensures that concurrent transactions do not interfere with each other.

• Durability ensures that once a transaction is committed, it will persist even in the...read more

A callout Apex class is used to make HTTP requests from Salesforce to external services.

• Create a class that implements the HttpCallout interface

• Use the HttpRequest class to define the request

• Use the HttpResponse class to handle the response

Use DateTime.ParseExact method to convert Date to DateTime.

• Use DateTime.ParseExact method to convert a string representation of a date to a DateTime object.

• Specify the format of the date string using a format string.

• Example: DateTime.ParseExact("2022-10-15", "yyyy-MM-dd", CultureInfo.InvariantCulture)

Developed a web application for tracking personal fitness goals and progress

• Used HTML, CSS, and JavaScript for front-end development

• Implemented RESTful APIs using Node.js and Express for back-end functionality

• Utilized MongoDB for database management

• Incorporated charting libraries like Chart.js for visualizing progress data

A batch class is used in Salesforce to process records in bulk.

• Batch classes in Salesforce are used to process large volumes of records asynchronously.

• They are implemented by implementing the Database.Batchable interface.

• Batch classes have three main methods: start, execute, and finish.

• Example: public class MyBatchClass implements Database.Batchable<SObject> { // implementation }