container.singleton("extractorFactory", ExtractorFactory.class, factory -> {
    factory.addExtractor("application/custom", container.getComponent("customExtractor"));
});
```

## Advanced Configuration

### Multi-Instance Crawling

```java
// Create multiple crawler instances
Crawler crawler1 = container.getComponent("crawler");
crawler1.setSessionId("session1");

        );
    })
    .error(throwable -> {
        // Handle error
        System.err.println("Error: " + throwable.getMessage());
    });
```

## Advanced Usage

### Index from Existing Documents

```java
import org.codelibs.fess.suggest.index.contents.document.ESSourceReader;

// Index suggestions from existing Elasticsearch documents