What is the principle behind hot deployment in Spring Boot?
The hot deployment feature in Spring Boot is achieved through the use of Spring Boot DevTools, which is a development toolkit that includes functions such as hot deployment.
The principle of hot deployment is that during the development phase, the application’s class files (including Java classes, HTML, CSS, etc.) are reloaded into the JVM without needing to restart the application. This allows developers to immediately see the results when making code changes, speeding up the development process.
Spring Boot DevTools implements hot deployment with two mechanisms.
- Class file reloading: DevTools will reload the class file using the underlying ClassLoader when it is modified, allowing changes to take effect immediately without the need to restart the application.
- Application context restart: In certain situations, modifications to a class file of an application may not be able to be reloaded, such as when a configuration file is changed. In these cases, DevTools will trigger a restart of the application context, which will reload the entire application, including any changes made to configuration files.
It is worth noting that hot deployment is only recommended for use during the development stage and not in a production environment. This is because hot deployment can lead to unpredictable behavior and performance issues. In a production environment, it is recommended to use the traditional deployment method, which involves rebuilding and restarting the application.
