Apache HttpCore is a set of low-level components for building HTTP services in Java. It provides the essential building blocks for creating HTTP clients and servers, allowing developers to handle HTTP requests and responses efficiently. The library is designed to be lightweight and flexible, making it suitable for various applications. One of the key features of Apache HttpCore is its support for both synchronous and asynchronous programming models. This flexibility enables developers to choose the best approach for their specific use cases, whether they are building simple applications or complex, high-performance systems.