HEPL - A Cavinkare Group Company Java Developer Interview Questions, Process, and Tips

OOPs stands for Object-Oriented Programming. It is a programming paradigm that uses objects to represent and manipulate data.

• OOPs is based on the concept of classes and objects.

• It focuses on encapsulation, inheritance, and polymorphism.

• Encapsulation ensures data hiding and abstraction.

• Inheritance allows the creation of new classes from existing ones.

• Polymorphism enables objects to take on multiple forms.

• Example: In Jav...read more

Multithreading is the concurrent execution of two or more threads to achieve maximum utilization of CPU.

• Multithreading allows multiple threads to run concurrently within a single program.

• It improves performance by utilizing idle CPU time and executing multiple tasks simultaneously.

• Threads can communicate and share resources, but synchronization is required to avoid conflicts.

• Examples include running background tasks wh...read more

Exception handling is a mechanism in Java to handle runtime errors and prevent program crashes.

• Exception handling allows programmers to catch and handle errors that occur during program execution.

• It involves using try-catch blocks to catch exceptions and provide alternative code to handle the error.

• The catch block specifies the type of exception to catch and the code to be executed when that exception occurs.

• Java provi...read more

Inner join is used to combine rows from two or more tables based on a related column between them.

• Use INNER JOIN keyword in SQL to perform inner join

• Specify the columns to join on using ON keyword

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column

Object-oriented programming concepts in Java

• OOPs stands for Object-Oriented Programming

• Key concepts include classes, objects, inheritance, polymorphism, encapsulation

• Java supports OOPs principles like abstraction, encapsulation, inheritance, and polymorphism

Object-oriented programming concepts in Java

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

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

• Polymorphism: ability of an object to take on many forms

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

A for loop is a control flow statement for iterating a specific number of times.

• Used to iterate over a range of values or elements in an array

• Consists of initialization, condition, and increment/decrement expressions

• Example: for(int i=0; i<5; i++) { System.out.println(i); }

Collections in Java are frameworks that provide an architecture to store and manipulate a group of objects.

• Collections provide interfaces (List, Set, Map) and classes (ArrayList, LinkedList, HashSet, HashMap) to store and manipulate groups of objects.

• Collections framework includes algorithms to manipulate data structures like sorting, searching, etc.

• Collections are more flexible and efficient than arrays in Java.

• Exampl...read more

Exception handling in Java is a mechanism to handle runtime errors and prevent program crashes.

• Use try-catch blocks to handle exceptions

• Use finally block to execute code regardless of exception

• Use throw keyword to manually throw exceptions

• Use throws keyword in method signature to declare exceptions that can be thrown