Java Spring Boot 3 Years Experience Interview

Summary

In this interview, Anit Kumar, a Java and Spring developer with three years of experience at Accenture, discusses his work on a telecommunications project in Australia. He explains his role in developing microservices using Java and Spring Boot, and touches on various technical topics such as static blocks, collections, HashMaps, reflection, functional interfaces, and streams. Anit also shares his knowledge of Spring Boot's configuration, Bean scopes, and design patterns like Singleton, emphasizing the practical applications of these concepts in his projects.

Takeaways

• 😀 Anit Kumar, with three years of experience in Java and Spring, is currently working with Accenture in Pune, India.
• 🔍 Anit has worked on a telecommunications project based in Australia, focusing on Java, Spring, and microservices.
• 🛠️ He has experience with tools such as AWS, Bamboo, and Sonar, in addition to his work with Java and Spring.
• 📝 Anit discussed the possibility of printing to the console without a main method in Java, highlighting the use of static blocks.
• 🔑 Anit clarified that multiple static blocks can be used in Java for initializing static data members.
• 🚫 He noted that multiple finally blocks are not allowed in Java due to the one-to-one correspondence with try-catch pairs.
• 📚 Anit shared his knowledge on Java collections, explaining the difference between List and Set, emphasizing order and duplicates.
• 🔄 Anit mentioned the use of HashMaps and the importance of overriding hashCode and equals methods when using classes as keys.
• 🔍 He expressed unfamiliarity with Java Reflection, indicating it was not a part of his project experience.
• 🔄 Anit explained functional interfaces in Java, including their use in sorting and iterating over collections.
• 🚀 He demonstrated understanding of Spring Boot, differentiating it from Spring by its reduced configuration needs and embedded server.

Q & A

What is the professional background of Anit Kumar?

Anit Kumar has three years of experience in Java and Spring, and he is currently working with Accenture in Pune, India. He has also worked with technologies such as AWS, Bamboo, and SonarQube.

What type of project has Anit Kumar worked on?

Anit has worked on a telecommunication project based in Australia, involving the use of Java, Spring, and microservices.

Can Java code print to the console without a main method?

Yes, it is possible to print to the console without a main method by using a static block, which executes before the main method.

What is the purpose of a static block in Java?

A static block is used to initialize static data members and can also include code to be executed before the main method, such as printing to the console.

What is the difference between a List and a Set in Java collections?

A List is an ordered collection that allows duplicate elements and supports index-based operations, while a Set is an unordered collection that does not allow duplicates and does not support index-based operations.

Can a class be used as a key in a HashMap?

A class can be used as a key in a HashMap if it is immutable, like a wrapper class. If a class is mutable, it can still be used by overriding the hashCode and equals methods to ensure consistent behavior.

What is reflection in Java?

Reflection is a feature in Java that allows the modification of the behavior of methods, classes, and interfaces at runtime. It provides methods like getClass, getMethod, and getConstructor to inspect and manipulate classes.

What is a functional interface in Java?

A functional interface in Java is an interface that contains only one abstract method. Examples include Runnable, Iterator, and Comparator.

Can a functional interface extend another interface?

A functional interface cannot extend another interface that contains abstract methods, as it would violate the rule of having only one abstract method. However, it can inherit interfaces with default or static methods.

What is the difference between filter and map functions in the Stream API?

The filter function is used to discard elements from a stream based on a condition, reducing the size of the resulting collection. The map function is used to transform each element of the stream into a new form, such as mapping integers to their square roots, without reducing the size of the collection.

What is the basic difference between Spring and Spring Boot?

Spring Boot simplifies the bootstrapping and development of new Spring applications by providing default configurations and an embedded server, reducing the need for extensive XML configuration and making it easier to create stand-alone, production-grade Spring-based applications.

What are the various scopes of a Bean in Spring?

In Spring, the scopes of a Bean include Singleton (one instance per Spring IoC container), Prototype (a new instance every time one is requested), and for web applications, Request (one instance per HTTP request) and Session (one instance per HTTP session).

What is the purpose of the @Configuration annotation in Spring?

The @Configuration annotation is used to indicate that a class contains bean definitions and methods annotated with @Bean. It allows for the configuration of application-specific settings.

Can you explain the Singleton design pattern and how to prevent cloning of a Singleton object?

The Singleton design pattern ensures that a class has only one instance and provides a global point of access to it. To prevent cloning, the clone method can be overridden to throw a CloneNotSupportedException, ensuring that no additional instances of the Singleton class can be created.