ServletContainerInitializer (Servlet 5.0 API Documentation - Apache Tomcat 10.0.27)

```
public interface ServletContainerInitializer
```
ServletContainerInitializers (SCIs) are registered via an entry in the file META-INF/services/jakarta.servlet.ServletContainerInitializer that must be included in the JAR file that contains the SCI implementation.
SCI processing is performed regardless of the setting of metadata-complete. SCI processing can be controlled per JAR file via fragment ordering. If absolute ordering is defined, then only the JARs included in the ordering will be processed for SCIs. To disable SCI processing completely, an empty absolute ordering may be defined.
SCIs register an interest in annotations (class, method or field) and/or types via the HandlesTypes annotation which is added to the class.

Since:

Servlet 3.0

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`onStartup(java.util.Set<java.lang.Class<?>> c, ServletContext ctx)`	Receives notification during startup of a web application of the classes within the web application that matched the criteria defined via the `HandlesTypes` annotation.

- Method Detail
  - onStartup
```
void onStartup(java.util.Set<java.lang.Class<?>> c,
               ServletContext ctx)
        throws ServletException
```
    Receives notification during startup of a web application of the classes within the web application that matched the criteria defined via the HandlesTypes annotation.
    
    Parameters:
    
    c - The (possibly null) set of classes that met the specified criteria
    
    ctx - The ServletContext of the web application in which the classes were discovered
    
    Throws:
    
    ServletException - If an error occurs