Which Android component is initialized first before the onCreate method of the Application class?

The first component to be initialized in Android before the onCreate method of the Application class is the System Server — a system process that starts at device boot and is responsible for core system services. In the context of an application, before Application.onCreate() is called, the Zygote process is initialized — a process that forks new application processes.

If we talk specifically about initializing components within the application, then before Application.onCreate(), the Application class is loaded and its instance is created. However, system services and processes necessary for the application's operation are already running.

Thus, the system process Zygote is initialized first, which then creates the application process, and only after that is Application.onCreate() called.