10+ HostBooks Interview Questions and Answers

Answers to interview questions for Senior Software Engineer

• 1. CASE is used to provide conditional logic in SQL queries, while DECODE is used to perform conditional value substitution.

• 2. Primary keys are used to uniquely identify each record in a database table.

• 3. Procedures and functions are both database objects that encapsulate a series of SQL statements, but functions return a value while procedures do not.

• 4. SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(sal...read more

HashMap is not synchronized and allows null values, while Hashtable is synchronized and does not allow null values.

• HashMap is faster and preferred for non-thread-safe operations.

• Hashtable is slower but thread-safe.

• HashMap allows null values, while Hashtable does not.

• HashMap is not synchronized, so it is not suitable for concurrent operations.

• Hashtable is synchronized, making it suitable for concurrent operations.

Garbage collection is an automatic memory management process in which the system frees up memory occupied by objects that are no longer in use.

• Garbage collection is a feature of many programming languages, including Java and C#.

• It helps prevent memory leaks and reduces the burden of manual memory management.

• The garbage collector identifies and releases memory that is no longer referenced by any active objects.

• It works by tracing the object graph and marking objects that are s...read more

I delivered my code through version control systems like Git, following best practices for code review and testing.

• Used Git for version control to track changes and collaborate with team members

• Followed best practices for code review to ensure quality and consistency

• Implemented automated testing to catch bugs early and ensure code reliability

Dependency injection is a design pattern in which components are given their dependencies rather than creating them internally.

• Dependency injection helps in achieving loose coupling between classes.

• It allows for easier testing by providing a way to mock dependencies.

• There are three types of dependency injection: constructor injection, setter injection, and interface injection.

Java is a high-level programming language known for its portability, security, and object-oriented features.

• Java is platform-independent, meaning it can run on any device with a Java Virtual Machine (JVM).

• It is object-oriented, allowing for modular and reusable code.

• Java is known for its strong security features, such as sandboxing and encryption.

• It is widely used for developing web applications, mobile apps, and enterprise software.

• Popular frameworks and libraries in Java in...read more

A variable is a named storage location in a computer's memory that can hold a value.

• Variables are used to store and manipulate data in a program.

• They have a name, a type, and a value.

• The value of a variable can be changed during program execution.

• Variables can be used to perform calculations, store user input, or hold intermediate results.

• Examples: int age = 25; float temperature = 98.6; string name = 'John';

Hashmap is a data structure that stores key-value pairs and allows for fast retrieval of values based on keys.

• Hashmap uses a hash function to map keys to indices in an array.

• It allows for constant time complexity O(1) for insertion, deletion, and retrieval operations.

• In case of collisions, separate chaining or open addressing techniques are used to handle them.

• Example: HashMap map = new HashMap<>(); map.put("key1", 1); int value = map.get("key1");

Inheritance in Java allows a class to inherit properties and behavior from another class.

• Allows a class to inherit fields and methods from another class

• Promotes code reusability and reduces redundancy

• Uses the 'extends' keyword to establish a parent-child relationship

• Child class can access non-private members of the parent class

Interface in Java is a blueprint of a class that defines a set of methods without implementation.

• Interfaces can have abstract methods and constants

• Classes can implement multiple interfaces

• Interfaces are used for achieving abstraction and multiple inheritance