10+ Lead Java Developer Interview Questions and Answers

Yes, I can create an application without the help of Google.

• I have a strong understanding of Java programming language and its libraries

• I have experience in developing applications without relying on external resources

• I have a good grasp of software development principles and best practices

Factory pattern is used to create objects without exposing the instantiation logic to the client. It can be used in inheritance to create objects of different subclasses.

• Factory pattern can be used to create objects of different subclasses without exposing the instantiation logic to the client

• It allows for flexibility in creating objects based on certain conditions or parameters

• Factory pattern can be used in inheritance to create objects of different subclasses based on the t...read more

Data of Microservice can be stored in a separate database or cache to ensure availability in case of issues with dependent Microservice.

• Store data in a separate database or cache to ensure availability in case of issues with dependent Microservice.

• Implement retry mechanisms to handle temporary failures in dependent Microservice.

• Use circuit breakers to prevent cascading failures in case of issues with dependent Microservice.

Group by a value using Java stream Api

• Use the Collectors.groupingBy() method to group elements by a specific value

• Provide a classifier function to specify the grouping criteria

• Example: Map> groupedByDepartment = employees.stream().collect(Collectors.groupingBy(Employee::getDepartment));

Comparable and Comparator are interfaces in Java used for comparing objects.

• Comparable is used for natural ordering of objects, implemented in the class of the object being compared.

• Comparator is used for custom ordering of objects, implemented in a separate class.

• Example: Comparable interface is used in String class for natural ordering, while Comparator interface can be used to sort a list of custom objects based on specific criteria.

Singleton design pattern was used in the project.

• Ensures a class has only one instance and provides a global point of access to it

• Used when only one instance of a class is needed throughout the system

• Example: Database connection manager, Logger classes

Program to sum two arrays in place without using extra space

• Iterate through the arrays from right to left, adding the elements and storing the sum in the first array

• Handle carry while adding the elements

• Ensure to handle cases where arrays have different lengths

Monolithic is a single, large application while microservices is a collection of small, independent services.

• Monolithic architecture is a single, self-contained unit where all components are interconnected and interdependent.

• Microservices architecture breaks down the application into smaller, loosely coupled services that communicate with each other through APIs.

• Monolithic applications are typically easier to develop and test but harder to scale and maintain.

• Microservices all...read more

Global exception handling is a mechanism to handle exceptions that occur throughout an application.

• Global exception handling allows for centralized handling of exceptions in an application.

• It helps in maintaining a consistent error handling strategy across the application.

• By using global exception handling, developers can catch and handle exceptions at a higher level in the application.

• Examples include using a global exception handler to log errors, display user-friendly erro...read more

Spring Boot is a framework that simplifies the development of Java applications by providing pre-configured settings and tools.

• Spring Boot eliminates the need for manual configuration by providing defaults for most settings.

• It allows for the creation of stand-alone, production-grade Spring-based applications.

• Spring Boot includes embedded servers like Tomcat, Jetty, or Undertow for easy deployment.

• It promotes convention over configuration, reducing the amount of boilerplate co...read more

Microservices are a software development technique where applications are broken down into smaller, independent services that work together.

• Microservices are small, independent services that can be developed, deployed, and scaled independently.

• Each microservice typically focuses on a specific business function and communicates with other services through APIs.

• Microservices promote flexibility, scalability, and resilience in software development.

• Examples of companies using mic...read more

Oops concepts in Java are fundamental principles of object-oriented programming such as inheritance, polymorphism, encapsulation, and abstraction.

• Inheritance: Allows a class to inherit properties and behavior from another class.

• Polymorphism: Ability of an object to take on many forms.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Abstraction: Hiding the implementation details and showing only the necessary features of an object.

I led a team in developing a Java project for a financial institution.

• Developed a secure online banking platform using Java EE

• Implemented features such as account management, transaction history, and fund transfers

• Utilized Spring framework for dependency injection and Hibernate for database interaction