| Interface | Description | 
|---|---|
| Engine | 
 Engine interface. 
 | 
| Class | Description | 
|---|---|
| EngineId | 
 Engine ID used to authenticate instances of  
Loader. | 
| LayeredEngine | 
 Engine based on instances of  
LayeredClassLoader. | 
| LayeredEngine.Builder | 
 Builder for instances of  
LayeredEngine. | 
| Loader | 
 Wrapper for a  
SourceClassLoader that can only be used
 by the Engine that created it. |