WizTools.org is a Java implementation of the oEmbed specification. Sample usage:

import org.wiztools.oembed.*;
import java.net.URL;

...

OEmbedUrlBuilder builder = new OEmbedUrlBuilder("http://www.youtube.com/oembed");
builder.addUrl("http://www.youtube.com/watch?v=DcexJQM-8W0")
       .addFormatXml();

URL url = builder.build();

// Now execute:
OEmbedExecutor exec = new OEmbedHttpExecutor();
OEmbedResponse response = exec.get(url);

// Print the result:
System.out.println(response.getHtml());