NSE.IT Interview Questions, Process, and Tips

Collections in Java are classes that implement data structures like lists, sets, maps, etc.

• Collections are used to store and manipulate groups of objects

• List interface is used to store ordered elements, ArrayList and LinkedList are implementations of List

• Set interface is used to store unique elements, HashSet and TreeSet are implementations of Set

• Map interface is used to store key-value pairs, HashMap and TreeMap are i...read more

There are three types of JDBC statements: Statement, PreparedStatement, and CallableStatement.

• Statement: used for executing a static SQL statement

• PreparedStatement: used for executing a precompiled SQL statement with parameters

• CallableStatement: used for executing a stored procedure or function

OOPS concepts are the fundamental principles of Object-Oriented Programming. There are four pillars of OOPS concepts.

• Encapsulation - binding data and functions together in a single unit (class).

• Abstraction - hiding implementation details and showing only necessary information to the user.

• Inheritance - creating a new class from an existing class, inheriting properties and methods.

• Polymorphism - ability of an object to t...read more

IOC container is a software component that manages the dependencies between objects.

• IOC stands for Inversion of Control

• It is used to achieve loose coupling between objects

• It allows objects to be created and wired together at runtime

• Examples include Spring Framework's ApplicationContext and Google Guice's Injector

• IOC containers use dependency injection to provide objects with their dependencies

Joins are used to combine data from two or more tables based on a related column.

• Inner join returns only the matching rows from both tables.

• Left join returns all rows from the left table and matching rows from the right table.

• Right join returns all rows from the right table and matching rows from the left table.

• Full outer join returns all rows from both tables.

• Cross join returns the Cartesian product of both tables.

Multi-threading is a technique of executing multiple threads concurrently. New threads can be started using the Thread class. Synchronization is the process of controlling the access to shared resources by multiple threads.

• Multi-threading allows multiple threads to run concurrently, improving performance.

• New threads can be started by creating a new instance of the Thread class and calling its start() method.

• Synchroniza...read more