The Sink interface is a generic markup language interface provided as a Java API. It contains several methods that encapsulate common text syntax. A start tag is denoted by xxxx() method and a end of tag by xxxx_() method.
For instance, you could do things like:
sink.paragraph(); sink.text( "my text" ); sink.paragraph_();
similar to this HTML markup:
<p>my text</p>
To find out more about the Sink API, you can read the Javadoc.