10+ HUREO Interview Questions and Answers

Primitive data types in Java are basic data types that are not objects.

• Primitive data types include int, double, float, char, boolean, byte, short, and long.

• Examples: int num = 10; double price = 19.99; char letter = 'A'; boolean flag = true;

Java is considered object-oriented because it supports the four main principles of OOP: encapsulation, inheritance, polymorphism, and abstraction.

• Java allows for the creation of classes and objects, which encapsulate data and behavior together.

• Inheritance is supported in Java, allowing classes to inherit attributes and methods from other classes.

• Polymorphism in Java allows objects to be treated as instances of their parent class, enabling flexibility in programming.

• Abstractio...read more

Just-in-time (JIT) is a feature in Java that compiles bytecode into native machine code at runtime.

• JIT improves the performance of Java programs by reducing the time needed for compilation.

• JIT is enabled by default in most Java virtual machines.

• JIT can be disabled using the -Xint option.

• JIT can also be configured using various options such as -XX:CompileThreshold and -XX:MaxInlineLevel.

HashMap is a key-value pair collection while HashSet is a collection of unique elements.

• HashMap stores key-value pairs while HashSet stores unique elements.

• HashMap allows duplicate values but keys must be unique, while HashSet does not allow duplicates.

• HashMap uses keys to retrieve values, while HashSet does not have keys and values are the same.

• Example: HashMap map = new HashMap<>(); HashSet set = new HashSet<>();

JVM stands for Java Virtual Machine, it is an abstract computing machine that enables a computer to run Java programs.

• JVM is responsible for converting Java bytecode into machine code that can be executed by the computer's processor.

• It provides a platform-independent execution environment for Java programs.

• JVM manages memory, handles garbage collection, and provides security features for Java applications.

• Examples of JVM implementations include Oracle HotSpot, OpenJ9, and Gra...read more

JIT stands for Just-In-Time compiler in Java, which compiles Java bytecode into native machine code at runtime.

• JIT compiler improves the performance of Java applications by compiling bytecode into native machine code on-the-fly.

• It identifies and optimizes frequently executed code paths, resulting in faster execution.

• JIT compiler is a part of Java Virtual Machine (JVM) and helps in achieving high performance without the need for manual intervention.

• Example: When a Java program...read more

Wrapper classes in Java are classes that allow primitive data types to be accessed as objects.

• Wrapper classes provide a way to convert primitive data types into objects.

• They are used when an object is required, such as in collections or generics.

• Examples include Integer for int, Double for double, Boolean for boolean, etc.

Optional class is used to handle null values in Java, preventing NullPointerExceptions.

• Optional class was introduced in Java 8 to provide a more elegant way of handling null values.

• It encourages developers to explicitly handle the presence or absence of a value, rather than relying on null checks.

• Optional class has methods like isPresent(), get(), orElse(), etc. to work with optional values.

• Using Optional class can make code more readable and less error-prone.

• Example: Optiona...read more

Java is object-oriented to promote code reusability, modularity, and maintainability.

• Java's object-oriented approach allows for the creation of reusable code components called objects.

• Objects encapsulate data and behavior, making it easier to manage and maintain code.

• Inheritance enables the creation of hierarchies and promotes code reuse.

• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• Abstraction and encapsulation help in hidin...read more

Primitive data types are basic data types provided by Java, such as int, double, boolean, char, etc.

• Primitive data types are predefined by the language and not objects

• They are used to store simple values directly in memory

• They have a fixed size and do not have any methods

• Examples include int for integers, double for floating-point numbers, boolean for true/false values, char for characters

JIT stands for Just-In-Time compiler. It is a part of the Java Virtual Machine (JVM) that compiles bytecode into machine code at runtime.

• JIT is responsible for improving the performance of Java applications by compiling frequently executed code into native machine code.

• It analyzes the code at runtime and identifies the hotspots, i.e., the code that is executed frequently.

• JIT compiles the hotspots into machine code and stores them in the code cache for future use.

• This process ...read more

OOPs concepts in C++ include inheritance, polymorphism, encapsulation, and abstraction.

• Inheritance allows a class to inherit properties and methods from another class.

• Polymorphism allows objects to take on multiple forms.

• Encapsulation hides the implementation details of a class from other objects.

• Abstraction focuses on the essential features of an object and hides the unnecessary details.

• Example: A car class can inherit properties from a vehicle class, and a sports car object...read more

JVM stands for Java Virtual Machine. It is a virtual machine that executes Java bytecode.

• JVM is responsible for running Java programs by interpreting bytecode.

• It provides platform independence by executing bytecode on different operating systems.

• JVM manages memory, performs garbage collection, and optimizes code execution.

• It consists of various components like class loader, bytecode verifier, interpreter, and just-in-time compiler.

• Examples of JVM implementations include Oracl...read more

Stream API is a set of classes in Java that allow processing collections of objects in a functional style. Lambda expressions are used to write concise code for functional interfaces.

• Stream API provides a way to perform operations on collections like filter, map, reduce, etc.

• Lambda expressions are used to define anonymous functions in a concise way.

• Example: List names = Arrays.asList("Alice", "Bob", "Charlie"); names.stream().filter(name -> name.startsWith("A")).forEach(Syste...read more

Encapsulation is the concept of bundling data and methods that operate on the data into a single unit.

• Encapsulation helps in hiding the internal state of an object and restricting access to it.

• It allows for better control over the data by preventing external code from directly modifying it.

• Example: A class 'Car' with private variables like 'model', 'year', and public methods like 'getYear()' and 'setModel()'.

OPPS stands for Object-Oriented Programming System. It is a programming paradigm that uses objects to represent real-world entities.

• OPPS focuses on the concept of objects and classes.

• It emphasizes encapsulation, inheritance, and polymorphism.

• Objects have attributes (data) and behaviors (methods).

• Classes are blueprints for creating objects.

• Encapsulation hides the internal details of an object.

• Inheritance allows classes to inherit properties and methods from other classes.

• Polym...read more