Zero to One

SOLID is an acronym that represents five design principles in object-oriented programming and software development. These principles were introduced by Robert C. Martin (also known as Uncle Bob) and are aimed at creating robust, maintainable, and scalable software systems. Each principle focuses on a specific aspect of software design and encourages developers to write code that is easy to understand, extend, and modify. Let's go through each of the SOLID principles: Single Responsibility Principle (SRP): The SRP states that a class should have only one reason to change, meaning it should have a single responsibility. In other words, a class should have one primary purpose or functionality, and it should not be responsible for more than that. This helps in keeping classes small, focused, and easier to maintain. When a class has multiple responsibilities, changes in one area can inadvertently affect other areas, leading to potential bugs and code entanglement.
 Open/Closed Principle

 Some commonly used methods of `MongoOperations` in Spring Data MongoDB, along with examples: 1. Insert Documents:    - insert(Object objectToSave)`: Inserts a document into the collection.      YourEntity entity = new YourEntity("value1", "value2");      mongoOperations.insert(entity); 2. Find Documents:    - find(Query query, Class<T> entityClass)`: Finds documents matching the given query.      Query query = new Query(Criteria.where("field1").is("value1"));      List<YourEntity> result = mongoOperations.find(query, YourEntity.class);    - findOne(Query query, Class<T> entityClass)`: Finds the first document matching the query.      Query query = new Query(Criteria.where("field1").is("value1"));      YourEntity entity = mongoOperations.findOne(query, YourEntity.class);      3. Update Documents:    - updateFirst(Query query, Update update, Class<T> entityClass)`: Updates the first document matching the

 In Java, a functional interface is an interface that has only one abstract method. It is a key concept in functional programming and serves as the foundation for working with lambda expressions and method references. Java 8 introduced functional interfaces to support the new features of the Java language, such as streams and lambdas. Functional interfaces are annotated with the `@FunctionalInterface` annotation, which is optional but recommended. This annotation ensures that the interface has only one abstract method and generates a compile-time error if multiple abstract methods are declared. Although a functional interface can have default methods and static methods, it must have only one abstract method. The single abstract method in a functional interface represents the behavior that can be implemented by lambda expressions or method references. Lambda expressions allow you to define anonymous functions concisely. They provide a way to pass behavior as an argument to methods, maki

Design patterns in Java Design patterns are reusable solutions to common problems that occur in software design. They provide a structured approach to designing software and help improve code organization, maintainability, and flexibility. Here are some commonly used design patterns in Java: 1. Singleton Pattern:    - Ensures that a class has only one instance and provides a global access point to it.    - Example: `java.lang.Runtime` 2. Factory Pattern:    - Provides an interface for creating objects, but lets subclasses decide which class to instantiate.    - Example: `java.util.Calendar` 3. Observer Pattern:    - Defines a one-to-many dependency between objects, so that when one object changes state, all its dependents are notified and updated automatically.    - Example: `java.util.Observable` and `java.util.Observer` 4. Builder Pattern:    - Separates the construction of complex objects from their representation, allowing the same construction process to create various representat