Celebal Technologies Node JS Developer Interview Questions, Process, and Tips

Encapsulation is the process of hiding implementation details and providing access to only necessary information.

• Encapsulation helps in achieving data abstraction and information hiding.

• It allows for better control over data and prevents unauthorized access.

• In Java, encapsulation is achieved through the use of access modifiers such as private, public, and protected.

• For example, a class may have private variables that c...read more

A string is a sequence of characters used to represent text in programming.

• Strings are often used for storing and manipulating text data.

• In Java, strings are represented by the String class.

• Strings can be concatenated using the + operator.

• Strings are immutable, meaning they cannot be changed once created.

• Examples of string literals include "hello world" and "42".

The question is asking about the candidate's knowledge in Core Java, Spring, Hibernate, Spring Boot, SQL, and AngularJS.

• Core Java is the foundation of Java programming language.

• Spring is a popular framework for building Java applications.

• Hibernate is an ORM tool used for mapping Java objects to database tables.

• Spring Boot is a framework for building microservices.

• SQL is a language used for managing relational databases...read more

To connect 2 DBs from a Spring Boot application, configure multiple data sources and use JdbcTemplate or EntityManager for each DB.

• Configure multiple data sources in the application.properties file

• Create separate configuration classes for each data source

• Use JdbcTemplate or EntityManager to interact with each DB

• Specify the appropriate data source in the repository or service classes

Abstract method implementation is mandatory while default method is optional.

• Abstract method has no implementation in the abstract class and must be implemented by the subclass.

• Default method has a default implementation in the interface and can be overridden by the implementing class.

• Abstract method is used to enforce a contract while default method is used to provide a default behavior.

• Example: abstract method - publ...read more

Java is a high-level, object-oriented programming language used to develop applications for various platforms.

• Java is platform-independent and can run on any platform with a JVM.

• It is used for developing web, mobile, desktop, and enterprise applications.

• Java has a vast library of pre-built classes and APIs.

• It supports multithreading, exception handling, and garbage collection.

• Java is widely used in the industry for its...read more

Java is a popular, versatile, and reliable programming language used for developing a wide range of applications.

• Java is platform-independent, making it easy to write code once and run it on multiple platforms.

• It has a vast library of pre-built classes and APIs, making development faster and easier.

• Java is highly secure and provides built-in features for encryption and authentication.

• It is widely used in enterprise app...read more