In the modern software development landscape, APIs (Application Programming Interfaces) have become the backbone of system integration. As applications grow in complexity and scale, the need for clear, consistent, and accessible API documentation becomes paramount. This is where Swagger, now known as the OpenAPI Specification, comes into play.

Database schema management presents one of the most challenging aspects of application development. As applications evolve, database structures must adapt accordingly, creating a need for reliable, automated, and version-controlled database migrations. This is where Liquibase enters the picture as a powerful solution for managing database schema changes across different environments and development stages.

In the realm of microservices and distributed systems, monitoring and managing applications becomes increasingly complex. Spring Boot Actuator addresses this challenge by providing production-ready features that help you monitor and manage your application. This document explores Spring Boot Actuator in depth, covering its endpoints, implementation, and customization options.

Design patterns represent the best practices used by experienced software developers. They are solutions to general problems that software developers have encountered during software development. These patterns are not finished designs that can be transformed directly into code; they are templates that describe how to solve a problem that can be used in many different situations.

Configuration management is a critical aspect of any Spring application. As applications grow in complexity, the need for organized, flexible, and environment-specific configuration becomes increasingly important. Spring Framework provides robust mechanisms for handling configuration properties, allowing developers to externalize configuration and make applications more maintainable.

Multithreading is one of the most powerful features of Java, allowing developers to create applications that can perform multiple operations simultaneously. At its core, multithreading is about executing multiple threads concurrently within a single program. This capability is essential for developing efficient applications that can fully utilize modern multi-core processors and provide responsive user interfaces while performing background tasks.