HCLTech Java Developer Interview Questions and Answers

Exception handling is used to manage errors and maintain normal program flow in Java applications.

• Improves program reliability by catching runtime errors. Example: Catching a NullPointerException.

• Allows graceful degradation of functionality. Example: Providing a fallback mechanism when a service is unavailable.

• Facilitates debugging by providing stack traces. Example: Using printStackTrace() to identify the source ...read more

OOP is a programming paradigm based on objects, encapsulating data and behavior for modular and reusable code.

• Encapsulation: Bundling data and methods that operate on the data within one unit (e.g., a class).

• Inheritance: Mechanism to create a new class using properties and methods of an existing class (e.g., class Dog inherits from class Animal).

• Polymorphism: Ability to present the same interface for different und...read more

OOP, or Object-Oriented Programming, is a programming paradigm based on the concept of objects that contain data and methods.

• Encapsulation: Bundling data and methods that operate on the data within one unit, e.g., a class in Java.

• Inheritance: Mechanism to create a new class using properties and methods of an existing class, e.g., class Dog extends Animal.

• Polymorphism: Ability to present the same interface for diff...read more

An array is a data structure that stores a fixed-size sequence of elements of the same type, allowing for efficient data management.

• Arrays are indexed collections, starting from index 0. Example: String[] fruits = {"Apple", "Banana", "Cherry"};

• They have a fixed size, meaning once declared, the size cannot change. Example: String[] colors = new String[5];

• Arrays can hold primitive types or objects. Example: String[]...read more

An element in Java refers to a single item in a collection, such as an array or a list, representing data in a structured way.

• Array Element: In an array, each position holds an element, e.g., in int[] numbers = {1, 2, 3}, '2' is the second element.

• List Element: In a List, elements can be added or removed dynamically, e.g., List<String> names = new ArrayList<>(); names.add('Alice');

• Set Element: In a Set...read more

Virtual threads are lightweight threads managed by the Java Virtual Machine (JVM) to improve concurrency and scalability.

• Virtual threads are also known as fibers or lightweight threads.

• They are managed by the JVM and are more efficient than traditional threads.

• Virtual threads can be used to handle large numbers of concurrent tasks without the overhead of creating a new thread for each task.

• They are particularly us...read more