Jalan Infrastructure Interview Questions and Answers

Map is a built-in function in many programming languages that allows you to transform data from one form to another.

• Map applies a function to each element in an array and returns a new array with the transformed elements.

• It can also be used with other data structures like objects and sets.

• Internally, map uses a loop to iterate over each element in the array and applies the provided function to it.

• The transformed elements are then added to a new array which is returned as the ...read more

Constructors are special methods used to initialize objects, while methods are functions that perform specific tasks in a class.

• Constructors are called when an object is created, while methods are called to perform actions on objects.

• Constructors have the same name as the class and do not have a return type, while methods have a different name and can have a return type.

• Constructors are used to set initial values for object attributes, while methods are used to manipulate tho...read more

Difference between save and persist in Hibernate

• Save method returns the generated ID immediately while persist method returns void

• Save method can be called outside of a transaction while persist method must be called within a transaction

• Save method can be used with detached objects while persist method cannot

• Save method can be used with transient objects while persist method cannot

Hibernate is an ORM tool that simplifies database interactions in Java applications.

• Hibernate configuration involves setting up database connection details in hibernate.cfg.xml

• Entities are mapped to database tables using annotations or XML mapping files

• SessionFactory is created to obtain Session objects for database operations

• Transactions are managed using Session object to ensure data consistency

• Example: Entity class 'User' mapped to 'users' table, fetching user data using H...read more

OOPs concepts refer to Object-Oriented Programming principles such as Inheritance, Encapsulation, Polymorphism, and Abstraction.

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

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

• Polymorphism: Ability to present the same interface for different data types.

• Abstraction: Hiding the complex implementation details and showing only the necessary features.

I tested my last project by creating test cases, executing them, tracking defects in a defect tracking tool, and ensuring requirements traceability using RTM.

• Created test cases based on requirements and executed them to validate the functionality.

• Logged defects in a defect tracking tool such as Jira or Bugzilla, including detailed steps to reproduce and screenshots.

• Regularly communicated with developers to discuss and resolve defects.

• Maintained a Requirements Traceability Mat...read more

Static keyword is used to define class-level variables and methods that can be accessed without creating an instance of the class.

• Static variables are shared among all instances of a class.

• Static methods can be called without creating an object of the class.

• Static blocks are used to initialize static variables.

• Static import is used to import static members of a class.

Comparator is an interface used to compare objects in Java.

• Comparator is used to sort collections of objects based on specific criteria.

• It is often used with the Collections.sort() method.

• It can be used to sort objects based on multiple criteria.

• It can also be used to sort objects in reverse order.

• An example of using a Comparator is sorting a list of employees by their salary.