How to distinguish between compile-time code preprocessing and runtime code compilation?

Ahead-Of-Time (AOT) compilation is the process of converting source code or bytecode into machine code before the program runs. Just-In-Time (JIT) compilation occurs directly during the program's execution, when the code is executed.

How to distinguish:

• AOT compilation is performed in advance, allowing the program to start faster since the code is already compiled.
• JIT compilation happens dynamically, which allows optimizing the code for specific execution conditions but may increase startup time.

In Android, for example, a JIT compiler was used in Dalvik, but modern versions employ AOT compilation with ART, which improves performance and reduces delays when launching applications.